EVERY BOY'S MECHANICAL LIBRARY 




Every Boy's 

Mechanical 

Library 



MOTORS 



Every Boy's Mechanical Library 

By J. S. ZERBE, M.E. 
Price, per volume, 60 cents, Net. Postage extra. 



AUTOMOBILES 

This is a subject in which every boy is interested. While few 
mechanics have the opportunity to actually build an automobile, 
it is the knowledge, which he must acquire about every particular 
device used, that enables him to repair and put such machines in 
order. The aim of this book is to make the boy acquainted with 
each element, so that he may understand why it is made in that 
special way, and what the advantages and disadvantages are of 
the different types. To that end each structure is shown in 
detail as much as possible, and the parts separated so as to 
give a clear insight of the different functions, all of which are 
explained by original drawings specially prepared to aid the reader. 

MOTORS 

To the boy who wants to know the theory and the practical 
working of the different kinds of motors, told In language which 
he can understand, and illustrated with clear and explicit draw- 
ings, this volume will be appreciated. It sets forth the ground- 
work on which power is based, and includes steam generators, and 
engines, as well as wind and water motors, and thoroughly de- 
scribes the Internal Combustion Engine. It has special chapters 
on Carbureters, Ignition, and Electrical systems used, and par- 
ticularly points out the parts and fittings required with all de- 
vices needed in enginry. It explains the value of compounding, 
condensing, pre-heating and expansion, together with the methods 
used to calculate and transmit power. Numerous original illus- 
trations. 

AEROPLANES 

This work is not intended to set forth the exploits of aviators 
nor to give a history of the Art. It is a book of instructions in- 
tended to point out the theories of flying, as given by the pioneers, 
the practical application of power to the various flying structures; 
how they are built; the different methods of controlling them; 
the advantages and disadvantages of the types now in use; and 
suggestions as to the directions in which improvements are re- 
quired. It distinctly points out wherein mechanical flight differs 
from bird flight, and what are the relations of shape, form, size 
and weight. It treats of kites, gliders and model aeroplanes, 
and has an interesting chapter on the aeroplane and its uses in 
the great war. All the illustrations have, been specially prepared 
for the work. 



CUPPLES & LEON CO., Publishers, NEW YORK 



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Every Boy's Mechanical Library 



MOTORS 



. S. Z] 



BY 



J. Si ZERBE, M.E. 

Author of 
Aeroplanes — Automobiles 



ILLUSTRATED 



NEW YORK 
CUPPLES & LEON COMPANY 



- 



^ 



Copyright, 1915, by 
CUPPLES & LEON COMPANY 



l£ 



-76 bt 



*.£* 


APR 17 1915 


©CI.A397603 


' 



CONTENTS 

PAGE 

Introductory 1 

The Subject. The Inquisitive Trait. The Keasons 
for Doing Things. The Mystery of Mechanism. 
Curiosity which prompts Investigation. The Sum of 
Knowledge. 

Chapter I. Motors and Motive Power 5-21 

The Water Fall. Water moves in One Direction 
only. What is Energy. Stored or Potential Energy. 
Kinetic Energy. Friction. Resistance. Inertia. The 
Law of Bodies. Internal and External Resistance. 
Momentum. Energy Indestructible. Wind Power. 
Rectilinear Motion. Oscillating Motion. Movements 
in Nature. How Man Utilizes the Various Move- 
ments. Kinds of Potential Energy. The Power 
in Heat. Energy in Steam. Energy from the Sun. 
Power from Water. The Turbine. Calculating Power 
of a Turbine. Horse Power. Foot Pounds. Power 
and Time. Gravitation. Utilizing the pull of Grav- 
ity. Taking Advantages of Forces. Pitting Forces 
Against each Other. Centripetal and Centrifugal 
Forces. Power not Created. Developing the Power of 
Motors. Experimenting. 

Chapter II. The Steam Generator 22-31 

Water as an absorbant of Heat. Classification of 
Boilers. Mode of applying Heat. The Cylindrical 
Boiler. The Cornish Boiler. The Water Tube Boiler. 
Various Boiler Types. Compound Steam Boiler. 
Locomotive Steam Boiler. Vertical Steam Boiler. 

Chapter III. Steam Engines 32-59 

The Original Turbine Engine. The Reciprocating 
Engine. Atmospheric Engine. The Piston. Impor- 
tance of the Valve. Expanding the Steam. Balanced 
Valve. Rotary Valve. Engine Accessories. Efficiency 
of Engines. How Steam acts in a Cylinder. Indi- 
cating the Engine. Mean Efficiency. Calculating 
Horse Power. Condensation. Atmospheric Pressure. 



CONTENTS 

PAGE 

The Condenser. Pre-heating. Superheaters. Com- 
pounding. Triple and Quadruple Expansion Engines. 
The Steam Turbine. Pressure and Velocity. Form of 
Blades. Compounding the Jet. 

Chapter IV. Fuels and Combustion 60-67 

Solid Fuels. Liquid Fuels. Combustion. Oxida- 
tion. The Hydro-Carbon Gases. Oxygen and the At- 
mosphere. Internal Combustion. Vaporizing Fuel. 
Explosion by Heat Compression. How Compression 
Heats. Elasticity of Gases. Advantages of Compres- 
sion. The Necessity of Compression. 

Chapter V. The Internal Combustion Engine . . 68-82 

Fixed Gases. Gas Engines. Energy of Carbon and 
Hydrogen. The Two-Cycle Type. Advantages of the 
Two-Cycle Engine. The Four-Cycle Engine. The Four 
Cycles. Ignition Point. Advantages of the Four- 
Cycle Type. The Loss in Power. Engine Construc- 
tion. Valve Grinding. The Crank Shaft. The 
Cams. 

Chapter VI. Carbureters 83-101 

Functions of a Carbureter. Rich Mixtures. Lean 
Mixtures. Types of Carbureters. The Sprayer. The 
Surface Type. Governing a Carbureter. Primary Air. 
Needle Valve. Secondary Air. Requirements in a 
Carbureter. Size of a Carbureter. Rule for Size of 
Carbureters. The Throttle. Flooding. Adjustability. 
Surface Carbureters. Float Chamber. 

Chapter VII. Ignition. Low Tension System . 102-120 

Electricity. Magnetism. The Armature. Charac- 
teristics of Electricity. Make and Break System. 
Voltage. High and Low Voltage. Low Tension 
method. Disadvantages of Make and Break. Am- 
peres. Resistance. Direct Current. Alternating Cur- 
rent. Induction. Generating Electricity. Primary 
Battery. Making a Dry Cell. Energy in a cell. 
Wiring Methods. Series Connection. Multiple Con- 
nection. Series Multiple. Watts. Testing a Cell. 
Testing with Instruments. Simple Battery Make and 
Brake System. To Advance the Spark. The Magneto 
in the Circuit. Magneto Spark Plug. 



CONTENTS 

PAGE 

Chapter VIII. Ignition, High Tension 121-140 

Magnetos. Alternating Current. Cutting Lines of 
Force. Plurality of Loops. The Electro Magnet. The 
Dynamo Form. The Magneto Form. Advantages of 
the Magneto. Induction Coil. Changing the Current. 
Construction of a Coil. Primary Coil. Secondary 
Coil. Contact Maker. High Tension with Battery and 
Coil. Metallic Core for Induction Coil. The Con- 
denser. Operations of a Vibrator Coil. The Distribu- 
tor. Circuiting with Distributor. 

Chapter IX. Mechanical Devices Utilized in Power 141-157 

The Unit of Time. Horse Power. Proney Brake. 
Reversing Mechanism. Double Eccentric Reversing 
Gear. Balanced Slide Valve. Balanced Throttle 
Valve. Engine Governors. Injectors. Feed Water 
Heaters. 

Chapter X. Valves and Valve Fittings .... 158-171 

Check Valve. Gate Valve. Globe Valve. The 
Corliss Valve. Corliss Valve-operating Mechanism. 
Angle Valve. Rotary Valves. Rotable Engine Valves. 
Throttle Valves. Blow-off Valves. Pop- Safety Valves. 

Chapter XL Cams and Eccentrics 172-178 

Simple Cams. Wiper Wheels. Cylindrical Cam 
Motion. Eccentrics. Triangularly-formed Eccentrics. 

Chapter XII. Gears and Gearing 179-190 

Racks and Pinions. Mangle Rack. Controlling the 
Pinion. Dead Center. Crank Motion Substitute. 
Mangle Wheels. Quick Return Motion. Accelerated 
Motion. Quick-return Gearing. Scroll Gearing. 

Chapter XIII. Special Types of Engines .... 191-201 

Temperatures. Artificial Heat. Zero. Liquids and 
Gases. Refrigeration. Rotary Engines. Caloric En- 
gines. Adhesion Engines. 

Chapter XIV. Enginery in the Development of the 

Human Race 202-207 

Power in Transportation. Power vs. Education and 
the Arts. Lack of Power in the Ancient World. 
The Early Days of the Republic. Lack of Cohesive- 



CONTENTS 

PAGE 

ness in Countries Without Power. The Railroad as 
a Factor in Civilization. The Wonderful Effects of 
Power. England as a User of Power. The Automo- 
bile. High Character of Motor Study. The Unlimited 
Field of Power. 

Chapter XV. The Energy of the Sun, and How Heat 

is Measured 208-216 

Fuel Economy. Direct Conversion. The Measure- 
ment of Heat. Caloric. Material Theory. Heat 
Transmitted in Three Ways. Conduction. Convec- 
tion. Radiation. 

Glossary 217 



LIST OF ILLUSTRATIONS 

FIG. PAGE 

1. Undershot Wheel 13 

2. Overshot Wheel 14 

3. Primitive Boiler 24 

4. Return Tubular Boiler 25 

5. Cornish, or Scotch Boiler 25 

6. Water Tube Boiler. End view 27 

7. Water Tube Boiler. Side view 29 

8. The Original Engine 33 

9. Horizontal Section of Tube 33 

10. Steam-Atmospheric Engine 35 

11. Simple Valve Motion. First position 38 

12. Simple Valve Motion. Second position 38 

13. Effective pressure in a Cylinder 42 

14. Indicating pressure line 44 

15. Indicating the Engine 45 

16. Compound Engine 53 

16a. Relative Piston Pressures 54 

17. Changing Pressure into Velocity 55 

18. Reaction against Air 56 

19. Reaction against Surface 56 

20. Turbine. Straight Blades 57 

21. Curved Blades 58 

22. Compound Turbine 58 

23. Two-Cycle Engine. First position 71 

24. Two-Cycle Engine. Second position 73 

25. Two-Cycle Engine. Third position 73 

26. Four-Cyele Engine. First position 75 

27. Four-Cycle Engine. Second position 7"> 

28. Four-Cycle Engine. Third position 76 

29. Four-Cycle Engine. Fourth position 76 

30. Valve Grinding 81 



LIST OF ILLUSTRATIONS 

FIG. PAGE 

31. Carbureter 87 

32. Carbureter 95 

33. Surface Carbureter 98 

34. Dry Cell 108 

35. Series Connection 109 

36. Multiple, or Parallel Connection 110 

37. Series-Multiple Connection Ill 

38. Circuit Testing 113 

39. Make and Break, with Battery 114 

40. Make and Break, with Magneto 117 

41. Magneto Spark Plug 119 

42. Illustrating Alternating Current 122 

43. Alternating Current. Second position 122 

44. Alternating Current. Third position 123 

45. Alternating Current. Fourth position 124 

46. Making the Circuit 125 

47. The Dynamo 126 

48. The Magneto 126 

49. Current by Induction 128 

50. Induction Coil 129 

51. Typical Induction Coil 130 

52. Contact Maker 131 

53. Typical Circuiting, Jump spark Ignition 132 

54. Metallic Core, Induction Coil 133 

55. Condenser '. 134 

56. Vibrator Coil and Connections 135 

57. The Distributer 137 

58. Circuiting with Distributer 138 

59. Illustrating the Unit of Time 142 

60. The Proney Brake 143 

61. Double Eccentric Reversing Gear 146 

62. Reversing Gear, Neutral 146 

63. Reversing Gear, Reversed 147 

64. Single Eccentric Reversing Gear 147 

65. Balanced Slide Valve 148 

66. Valve Chest. Double Port Exhaust 149 

67. Balanced Throttle-Valve 150 

68. Watt's Governor 151 



LIST OF ILLUSTRATIONS 

FIG. PAGE 

69. The Original Injector 152 

70. Injector with movable Combining Tube 154 

71. Feed Water Heater 156 

72. Check Valve 158 

73. Gate Valve 159 

74. Globe Valve 160 

75. Corliss Valve 162 

76. Corliss Valve-operating Mechanism 163 

77. Angle Valve 164 

78. Rotary-Valve 165 

79. Two-way Rotary 165 

80. Rotary Type 166 

81. Two- Way Rotary Type 166 

82. Butterfly Throttle 167 

83. Angle Throttle 167 

84. Slide Throttle 168 

85. Two-slide Throttle 168 

86. Blow-off Valve 169 

87. Safety Pop Valve 170 

88. Heart Shaped 173 

89. Elliptic 173 

90. Double Elliptic 173 

91. Single Wiper 174 

92. Double Wiper 174 

93. Tilting Cam 174 

94. Cam Sector 175 

95. Grooved Cam 175 

96. Reciprocating Motion 175 

97. Pivoted Follower for Cam 176 

98. Eccentric 177 

99. Eccentric Cam 177 

100. Triangularly-formed Eccentric 178 

101. Rack and Pinion 180 

102. Rack Motion 180 

103. Plain Mangle Rack 181 

104. Mangle Rack Motion 181 

105. Alternate Circular Motion 181 

106. Controlling Pinion for Mangle Rack 182 



LIST OF ILLUSTEATIONS 

FIG. PAGE 

107. Illustrating Crank-pin Movement 183 

108. The Dead Center 184 

109. Crank Motion Substitute 184 

110. Mangle Wheel 185 

111. Quick Return Motion 186 

112. Accelerated Circular Motion 187 

1 13. Quick Return Gearing 188 

114. Scroll Gearing 189 

115. Simple Rotary Engine 196 

116. Double-feed Rotary Engine 198 

117. Adhesion Motor 200 



INTRODUCTORY 

The motor is the great dominating factor in the 
world of industry. Every wheel and spindle; 
every shaft and loom, and every piece of mechan- 
ism which has motion, derives it from some sort 
of motor. 

The term motor has a wider significance than 
any other word. A steam engine is a motor, and 
so, also, is a dynamo, a water wheel or a wind 
mill. 

It would be just as descriptive to call a wind 
mill a wind motor, or a steam engine a steam 
motor, as to adhere to the old terms ; and, on the 
other hand, since it would be out of place to call a 
dynamo or a wind mill an engine, the word motor 
seems best adapted to express the meaning of 
every type of mechanism which transforms energy 
into motion. 

In considering the subject I shall proceed on 
the theory that the boy knows nothing whatsoever 
of the subject, nor the terms used to designate the 
various phases, subjects and elements. It must 
be elementary in its character, and wholly devoid 

of technical terms or sentences. 

1 



2 INTRODUCTORY 

While it is necessary to give information in a 
book of this character, on the methods for figuring 
out power, it must be done without resorting to 
the formulas usually employed in engineering 
works, as they are of such a nature that the boy 
must have some knowledge of the higher mathe- 
matics to follow out the calculations employed. 

Indeed, every phase should be brought within 
the mental view of the boy, and to do this may 
occasionally necessitate what might appear to be 
long drawn out explanations, all of which, it is 
hoped, will be the means of more clearly present- 
ing the subject. 

The opening chapters, which treat of the funda- 
mentals, will be as nearly complete as possible, 
and thus lay a foundation for the work we shall be 
called upon to perform, when we treat of the struc- 
tures of the different parts and devices in the vari- 
ous types of motors. 

The object is to explain power in its various 
phases, how derived, and the manner in which ad- 
vantage is taken of the elements, and substances 
with which we are brought into contact. The 
reasons for each step are plainly set forth with 
the view of teaching the boy what power means, 
rather than to instruct him how to make some 
particular part of the machinery. 

The Inquisitive Trait. — My experience has im- 



INTRODUCTORY 3 

pressed me with the universality of one trait in 
boys, namely, that of inquisitiveness. Put a ma- 
chine before a boy and allow him to dissect it, and 
his curiosity will prompt him to question the mo- 
tive for the particular construction of each part 
of its make-up. 

The Reasons for Doing Things. — He is inter- 
ested in knowing the reason why. Every boy has 
the spirit of the true investigator, — that quality 
which seeks to go behind or delve down deeply. 
This is a natural instinct. 

The Mystery of Mechanism. — If this taste is 
gratified, and he thereby learns the mystery of 
the machine, what a wonderful world is opened 
to him! The value of the lesson will depend, in 
a large measure, on the things which he has found 
out for himself. It is that which counts, because 
he never forgets that which he has dug out and 
discovered. 

Curiosity Which Prompts Investigation. — I re- 
call a farmer's boy whose curiosity led him to in- 
vestigate the binding mechanism of a reaper. It 
was a marvel to him, as it has been to many 
others. He studied it day after day, and finally, 
unaided mastered the art. That was something 
which could not be taken away from him. 

It was a pleasure to hear him explain its opera- 
tion to a group of boys, and men, too, in which he 



4 INTRODUCTORY 

used the knot itself to explain how the various 
fingers and levers cooperated to perform their 
functions. It was an open book to Mm, but there 
was not one in the group of listeners who could 
repeat the explanation. 

The Sum of Knowledge. — It is the self-taught 
boy who becomes the expert. The great inventors 
did not depend on explanations. A book of this 
character has a field of usefulness if it merely sets 
forth, as far as possible, the sum of useful knowl- 
edge which has been gained by others, so as to 
enable the boy to go forward from that point, and 
thus gain immensely in time. 

There is so much that has been developed in the 
past, with reference to the properties of matter, 
or concerning the utility of movements, and facts 
in the realm of weights, measures, and values of 
elements which he must deal with, that, as he 
studies the mechanical problems, the book becomes 
a sort of cyclopedia, more than a work designed 
to guide him in the building of special engines or 
motors. 

The Author. 



MOTORS 

CHAPTER I 

MOTORS AND MOTIVE POWER 

What makes the wheels turn round! This sim- 
ple question is asked over and over again. To 
reply means pages of answers and volumes of ex- 
planations. 

The Water Fall. — Go with me to the little 
stream I have in mind, and stand on the crest of 
the hill where we can see the water pouring down 
over the falls, and watch it whirling away over 
the rocks below. 

The world was very, very old, before man 
thought of using the water of the falls, or the 
rushing stream below, to grind his corn or to ren- 
der him other service. 

Water Moves in One Direction Only. — What 
the original man saw was a body of water moving 
in one direction only. When he wanted to grind 
corn he put it in the hollow of a rock, and then 
beat it with a stone, which he raised by hand at 



6 MOTORS FOR BOYS 

each stroke. In doing so two motions were re- 
quired in opposite directions, and it took thou- 
sands of years for him to learn that the water 
rushing along in one direction, could be made to 
move the stone, or the pestle of his primitive 
grinding mill, in two directions. 

It took him thousands of years more to learn 
another thing, namely, that the water could be 
made to turn the stone round, or rotate it, and thus 
cause one stone, when turning on another, to 
crush and grind the grain between them. 

Now, as we go along with the unfolding of the 
great question of motors, we must learn something 
of the terms which are employed, to designate the 
different things we shall deal with, and we ought 
to have some understanding of the sources of 
power. 

What Is Energy? — The running, as well as the 
falling water represent energy. This is some- 
thing which is in the thing, the element, or the 
substance itself. It does not come from without. 
It is not imparted to it by anything. 

Stored or Potential Energy. — At the top of 
the falls, look at that immense rock. It has been 
there for centuries. It, also, has energy. There 
is stored within it a tremendous power. You 
smile! Yes, the power has been there for ages, 
and now by a slight push it is sent crashing down 



MOTORS AND MOTIVE POWER 7 

the precipice. The power developed by that fall 
was thousands of times greater than the push 
which dislodged it. 

But, you say, the push against the stone rep- 
resented an external force, and such being the 
case, why do you say that power is within the 
thing itself! The answer is, that not one iota 
of the power required to push the stone off its 
seat was added to the power of the stone when it 
fell. Furthermore, the power required to dis- 
lodge the stone came from within me, and not from 
any outside source. 

Here we have two different forms of energy, 
but both represent a moving force. The power 
derived from them is the same. 

Kinetic Energy. — The energy of the falling 
water or stone is called Kinetic energy. In both 
cases the power developed came from within 
themselves and not from any exterior source. 

The difference between Potential and Kinetic 
Energy is therefore that Potential Energy repre- 
sents the capacity to do work, while Kinetic 
Energy is the actual performance of work. 

Friction. — In every form of energy there is al- 
ways something to detract from it or take away a 
portion of its full force, called friction. When a 
shaft turns, it rubs against the bearings, and more 
or less power is absorbed. 



8 MOTORS FOR BOYS 

When a wheel travels over the ground friction 
is ever present. The dislodging of the stone re- 
quired ten pounds of energy, but a thousand 
pounds was developed by the fall. The water 
rushing along its rocky bed has friction all along 
its path. 

Resistance. — This friction is a resistance to the 
movement of a body, and is ever present. It is 
necessary to go back and examine the reason for 
this. As long as the stone was poised at the top 
of the precipice it had latent or potential energy, 
which might be termed power at rest. When it 
fell it had power in motion. In both cases grav- 
ity acted upon the stone, and in like manner on 
the water pouring over the falls. 

Inertia. — Inertia or momentum is inherent in 
all things and represents the resistance of any 
body or matter, to change its condition of rest or 
standing still into motion, and is then called 
Inertia of Rest, or the resistance it offers to in- 
crease or decrease its speed when moving, and is 
then called Inertia of Motion. 

Inertia or momentum is composed by the weight 
of the body and its speed and is measured by mul- 
tiplying its weight by its speed. 

The law is, that when a body is at rest it will 
remain at rest eternally, and when in motion it 
will continue in motion forever, unless acted on 



MOTOKS AND MOTIVE POWER 9 

by some external force or resistance. An object 
lying on the ground has the frictional resistance 
of the earth to prevent its moving. When the 
object is flying through space it meets the air and 
has also the downward pull of gravity, which 
seek to bring it to rest. 

These resisting forces are less in water, and 
still less in gases, and there is, therefore, a state 
of mobility in them which is not found in solids. 

Internal and External Resistance. — All 
bodies are subject to internal, as well as external 
resistance. The stone on the cliff resisted the 
movement to push it over. Weight was the re- 
sisting internal force, but when the stone was 
moving through the air, the friction with the air 
created external resistance. 

Energy Indestructible. — There is another 
thing which should be understood, and that is the 
absolute indestructibility of energy. Matter may 
be changed in form, or in the direction of its mo- 
tion, by the change of kinetic into potential en- 
ergy, or vice versa, but the sum total of the en- 
ergy in the world is unalterable or constant. 

The tremendous power developed by the stone 
when it plunged through space and struck the 
rocks below, developed a heat at its impact. Thus 
the moving force which was a motion in one direc- 
tion was converted into another form of energy, 



10 MOTORS FOR BOYS 

heat. The expansion of the material exposed to 
the heat also represented energy. 

When powder explodes and absolutely changes 
the form of the substance, its volume of expansion, 
if it should be retained within a vessel, would per- 
form a certain amount of work, and the energy 
is thus transferred from one form to another 
without ceasing. 

Wind Power. — Primitive man also saw and felt 
the winds. He noted its tremendous power, but 
he could not see how a force moving in one direc- 
tion only could be utilized by him. 

Rectilinear Motion. — This movement of the 
wind in one direction, like the water flowing along 
the bed of the river, is called rectilinear motion. 
It required invention to convert rectilinear into 
circular motion. 

Oscillating Motion. — When he threshed his 
grain and winnowed it by shaking it to and fro, to 
rid it of the chafT, the idea of using the wind to 
produce an oscillating motion did not occur to 
him. After circular motion was produced, the 
crank was formed and thus the oscillating move- 
ment was brought about. 

Movements in Nature. — All movements in na- 
ture are simple ones, of which the following are 
illustrations : 



MOTORS AND MOTIVE POWER 11 

1. Rectilinear., which, as stated, means in a 
straight line. 

2. Circular, like the motion of the earth on its 
axis, once every twenty-four hours. 

3. Oscillatory, like a to and fro movement, 
the swaying branches of trees, or the swinging of 
a pendulum. 

How Man Utilizes the Various Movements. — 
What man has done is to utilize the great natural 
forces in nature in such a way as to produce these 
movements at will, in either direction, with 
greater or less speed, at regular or irregular in- 
tervals, and at such amplitudes as are required 
to perform the necessary work. 

Kinds of Potential Eneegy. — Now, materials 
have within themselves potential energy of vari- 
ous kinds. Thus, powder, if ignited, will burn, 
and in burning will expand, or explode, as we term 
it. This is true also of oils and gases. The ex- 
pansion pressure produced from such substances 
depends on the speed at which they will burn, and 
in so confining the burning substances that a 
great pressure is produced. 

The Power in Heat. — The pressure of all such 
substances against the confining medium depends 
on heat. Any gas which has 523 degrees of heat 
imparted to it will expand double its volume. If 



12 MOTOKS FOE BOYS 

one cubic inch of water is converted into steam the 
latter will occupy one cubic foot of space under 
atmospheric pressure, — that is, it will expand over 
1700 times. 

Energy in Steam. — If the steam thus generated 
is now subjected to 523 degrees of heat addi- 
tional, it will occupy over 3400 cubic inches of 
space. It will thus be seen why steam, gas, and 
gasoline engines are called heat engines, or heat 
motors. 

Energy From the Sun. — Many attempts have 
been made to utilize the heat of the sun, to turn 
machinery, but the difficulty has been to secure 
sufficient heat, on the one hand, and on the other 
to properly cool down the heated gases, so that the 
various liquid and solid fuels are required to 
make the heat transformations. 

Power From Water. — In the use of water two 
forms are available, one where the water is mov- 
ing along or falling in a constant open stream; 
and the other where the flowing water is confined 
and where its flow can be regulated and con- 
trolled. The latter is more available for two 
reasons : 

First: Economy in the use of water. 

Second : Ability to control the speed or move- 
ment of the motor. 

With running or falling streams a large surface 



MOTORS AND MOTIVE POWER 13 

is required, and the wheels turn slowly. Two well- 
recognized forms of wheels have been employed, 
one called the undershot, or breast wheel, shown 
in Fig. 1, and the other the overshot, illustrated in 
Fig. 2. 




T^UfJ. Undeiithoi- Wkeeh 



In both types it is difficult to so arrange them 
as to shut off the power or water pressure when 
required, or to regulate the speed. 

The Turbine. — Wheels which depend on the 
controllable pressure of the water are of the tur- 
bine type. The word is derived from the Latin 
word turbo, meaning to whirl, like a top. This is a 



14 



MOTORS FOR BOYS 



type of wheel mounted on the lower end of a verti- 
cal or horizontal shaft, within, or at the bottom, 
of a penstock. The perimeter of the wheel has 
blades, and the whole is enclosed within a drum, 
so that water from the penstock will rush through 




JTtg.2. Oi/erAhnt TJ/hffl 

the tangentially-formed conduit into the drum, 
and strike the blades of the wheel. 

A column of water one inch square and twenty- 
eight inches high weighs one pound, — or, to ex- 
press it in another way, the pressure at the bot- 



MOTORS AND MOTIVE POWER 15 

torn of such a column is one pound, and it is a 
pound for each additional 28 inches. 

If there should be a head or height of water 
column of seven feet, the pressure on each square 
inch of water at the bottom of the penstock would 
be three pounds to the square inch. Assuming 
the opening or duct leading to the wheel blades 
should be 12 x 12 inches, and also the blades be 
12 x 12 inches, the area would be equal to 144 
square inches, and this multiplied by three pounds 
would equal 432 pounds pressure against the 
blades. 

Calculating Power of a Turbine Wheel. — The 
power of such a wheel depends principally on two 
things. First, the arrangement of the blades with 
reference to the inflowing water; and, second, the 
discharge port, or ability of the water to free it- 
self from the wheel casing. 

Let us assume that the diameter of the wheel at 
the center of the blades is two feet, which would, 
roughly estimating, give a circumference of six 
feet, or a travel of each particular blade that dis- 
tance at each turn of the wheel. 

If the wheel turns one hundred times a minute, 
and this is multiplied by the circumference of the 
wheel (six feet), the result is 600 feet. This, 
again, multiplied by 432 pounds (which represents 
the pressure of the water on the entire discharge 



16 MOTORS FOR BOYS 

opening) , and we have a product of 259,200, which 
represents foot pounds. 

This means the same work as if 259,200 pounds 
would have been lifted through a space of one 
foot in one minute of time. To ascertain how 
much power has been developed we must know 
how many foot pounds there are in a horse power. 

Horse Power. — It is determined in this way: 
any force which is capable of raising 550 pounds 
one foot in one second of time, is developing one 
horse power. A man might have sufficient 
strength to raise such a weight once, twice, or a 
dozen times in succession, but if he should try 
to do it sixty times a minute he would find it a 
trying, if not impossible task. 

Foot Pounds. — If he should be able to lift 550 
pounds sixty times within a minute, he would have 
lifted 33,000 pounds one foot in one minute of 
time (550 X 60), and thus have developed one 
horse power. 

As the water wheel, in our calculations above, 
raised 259,200 pounds in that period of time, this 
figure divided by 33,000 shows that a little more 
than 7% horse power was developed, assuming, 
of course, that we have not taken into account any 
waste, or loss by friction, or otherwise. 

This method of determining one horse power 
should be carefully studied. Always keep in mind 



MOTORS AND MOTIVE POWER 17 

the main factor, 33,000 pounds, and this multi- 
plied by one foot, the result will be 33,000 foot 
pounds, — that is, one horse power. 

It would be just the same, however, if it were 
possible to raise one pound 550 times in one sec- 
ond, or one pound 33,000 times within a minute. 

Power and Time. — You are thus brought face 
to face with another thing which is just as impor- 
tant, namely, that, in considering power, time, as 
well as energy, must be considered. If a man, 
by superior strength, could be able to raise 550 
pounds once within a second, then skip a few sec- 
onds, take another hold, and again raise it that 
distance, he would not be developing one horse 
power for a minute, but only for one second while 
he lifted the weight. For the whole minute he 
would only develop a certain number of foot 
pounds, and less than 33,000 foot pounds. 

If, within a minute, he succeeded in raising it 
one foot for six times, this would be six times 550, 
equal to 3,300 foot pounds, or just one-tenth of 
one horse power for one minute ; so time is just as 
important as the amount lifted at each effort. 

Gravitation. — Now, let us examine power from 
another standpoint. Every attempt which man 
makes to produce motion is an effort to overcome 
some resistance. In many cases this is " weight 
or gravity. ' ' While humanity unceasingly antag- 



18 MOTORS FOR BOYS 

onizes the force of gravity it is constantly utiliz- 
ing the laws of gravitation. 

Utilizing the Pull of Gravity. — The boy la- 
boriously drags his sled to the top of the hill 
against gravity, and then depends on that force 
to carry him down. We have learned to set up 
one force in nature against the other. The run- 
ning stream ; the moving winds ; the tides ; the ex- 
pansive force of all materials under heat, are 
brought into play to counteract the great pre- 
vailing agency which seeks to hold everything 
down to mother earth. 

Utilizing Forces. — The Bible says : Blessed is 
he who maketh two blades of grass grow where 
one grew before. To do that means the utiliza- 
tion of forces. Improved machinery is enabling 
man to make many blades grow where one grew 
before. New methods to force the plow through 
the soil; to dig it deeper; to fertilize it; and to 
harvest it; all require power. 

Pitting Forces Against Each Other. — Man 
has discovered how to pit the forces of nature 
against each other, and the laws which regulate 
them. 

Centripetal and Centrifugal Forces. — Grav- 
ity, that action which seeks to draw all matter 
toward the center of the earth, is termed centri- 



MOTORS AND MOTIVE POWER 19 

petal force. But as the earth rotates on its axis 
another force is exerted which tends to throw sub- 
stances outwardly, like dirt flying from the rim 
of a wheel. This is called centrifugal force. 

Man utilizes this force in many ways, one of 
which is illustrated in the engine governor, where 
the revolving balls raise the arms on which they 
swing, and by that means the engine valve is regu- 
lated. 

Power Not Created. — In taking up the study 
of this subject start with a correct understanding 
of the source of all power. It is inherent in all 
things. All we can do is to liberate it, or to put 
the various materials in such condition, that they 
will exert their forces for our uses. (See Page 
nine, " Energy Indestructible.") 

A ton of coal, when burned, produces a certain 
amount of heat, which, if allowed to escape, will 
not turn a wheel. But if confined, it expands the 
air, or it may convert water into steam which will 
turn ponderous machinery. Niagara Falls has 
sent its great volume into the chasm for untold 
centuries, but it has never been utilized until 
within the last twenty years. The energy has 
been there, nevertheless; and so it is with every 
substance of which we have knowledge. 

The successive steps, wherein the experimenter 



20 MOTOKS FOR BOYS 

and the inventor have greatly improved on the 
original inventions, will be detailed as we go along 
through the different types of motors. 

Developing the Powee of Motoks. — This de- 
velopment in the art is a most fascinating study. 
It is like the explorer, forcing his way through a 
primeval forest. He knows not what is beyond. 
Often, like the traveler, he has met serious ob- 
structions, and has had to deviate from his course, 
only to learn that he took the wrong direction and 
had to retrace his steps. 

The study of motors and motive power is one 
which calls for the highest engineering qualities. 
In this, as in every other of the mechanical arts, 
theory, while it has an important function, occu- 
pies second place. 

Experimenting. — The great improvements have 
been made by building and testing; the advance 
has been step by step. Sometimes a most impor- 
tant invention will loom up as a striking example 
to show how a valuable feature lies hidden and 
undeveloped. 

An illustration of this may be cited with respect 
to the valve of the steam engine. For four hun- 
dred years there was no striking improvement in 
the valve. The various types of sliding and rock- 
ing valves were modified and refined until it was 
assumed that they typified perfection. At one 



MOTOES AND MOTIVE POWER 21 

stroke the Corliss valve made such an immense 
improvement that the marvel was as much in its 
simplicity as in its performance. 

The reasons and the explanations will be set 
forth in the section which analyzes valve motion. 
In this, as in other matters, it shall be our aim to 
explain why the different improvements were re- 
garded as epochs in the production of motors. 



CHAPTEE n 

THE STEAM GENERATOR 

The most widely known and utilized source of 
power is the steam engine. Before its discovery 
wind and water were the only available means, ex- 
cept the muscular power of man, horses and other 
animals, which was used with the crudest sort of 
contrivances. 

In primitive days men did not value their time, 
so they laboriously performed the work which ma- 
chinery now does for us. 

The steam engine, like everything else which 
man has devised, was a growth, and, singular as 
it may seem, the boiler, that vital part of the or- 
ganism, was, really, the last to receive due con- 
sideration and improvement. 

As the boiler is depended upon to produce the 
steam pressure, and since the pressure depends 
on the rapid and economical evaporation of water, 
the importance of the subject will be understood 
in treating of the steam engine. 

Water, as an Absorbant of Heat. — Water has 

the capacity to absorb a greater amount of heat 

22 



THE STEAM GENERATOR 23 

than any other substance. A pewter pot, which 
melts at 500 degrees, will resist 2000 degrees of 
heat if it is filled with water, since the lat- 
ter absorbs the heat so rapidly that the tempera- 
ture of the metal is kept near the boiling point of 
water, which is 212 degrees. 

Notwithstanding the great heat-absorbing qual- 
ities of water, a large portion of the heat of the 
fuel passes through the flues and escapes from the 
stack. This fact has caused inventors to devise 
various forms of boilers, the object being to pre- 
sent as large an area of water as possible to the 
heat of the burning fuel. How that was accom- 
plished we shall try to make plain. 

Classification of Boilers. — Numerous types of 
boilers have been devised, the object being, in all 
cases to evaporate the largest amount of water 
with the minimum quantity of fuel. All boilers 
may be put under two general heads, namely, those 
which contain a large quantity of water, and those 
which are intended to carry only a small 
charge. 

In the first division the boilers are designed to 
carry a comparatively small pressure, and in the 
latter high pressures are available. 

Mode of Applying Heat. — The most important- 
thing to fully understand is the manner in which 
heat is applied to the boiler, and the different 



24 



MOTORS FOR BOYS 



types which have been adapted to meet this re- 
quirement. 

The Cylindrical Boilee. — The most primitive 
type of boiler is a plain cylindrical shell A, shown 
in Fig. 3, in which the furnace B is placed below, 
so that the surface of the water in contact with 
the fire area is exceedingly limited. 

In such a type of boiler it would be impossible 




T^JQ. 3. Primitive Zollev 

for water to extract more than quarter the heat 
of the fuel. Usually it was much less. The next 
step was to make what is called a return tubular 
type in which the heat of the burning gases is 
conveyed to the rear end of the boiler, and then 
returned to the front end through tubes. 

Fig. 4 shows this construction. The head 
of the shell holds the ends of a plurality of tubes, 
and the products of combustion pass through the 



THE STEAM GENERATOR 



25 



conduit, below the boiler to the rear end, and are 
conducted upwardly to the tubes. As all the tubes 
are surrounded by water, it will absorb a large 
amount of the heat as the gases move through, 
and before passing out of the stack. 




'T^ig. 4. nefurx, Tulula r toiler . 




T^ig.d. Cornish , or Scotch toiler . 

The Coenish Boilee. — One of the most impor- 
tant inventions in the generation of steam was the 
Cornish boiler, which for many years was the rec- 
ognized type for marine purposes. It had the 
advantage that a large amount of water could be 
carried and be subjected to heat at all times. 



26 MOTORS FOR BOYS 

Aside from that it sought to avoid the great loss 
due to radiation. 

It will be seen from an examination of Fig. 5 
that the shell is made very large, and its length 
does not exceed its diametrical measurement. 
Two, and sometimes three, fire tubes are placed 
within the shell, these tubes being secured to the 
heads. Surrounding these fire tubes, are numer- 
ous small tubes, through which the products of 
combustion pass after leaving the rear ends of the 
fire tubes. 

In these boilers the tubes are the combustion 
chambers, and are provided with a grating for 
receiving the coal, and the rear ends of the tubes 
are provided with bridge walls, to arrest, in a 
measure, the free exit of the heated gases. 

These boilers would be very efficient, if they 
could be made of sufficient length to permit the 
water to absorb the heat of the fuel, but it will 
be seen that it would be difficult to make them of 
very great length. If made too small diametri- 
cally the diameter of the fire boxes would be re- 
duced to such an extent that there would not be 
sufficient grate surface. 

It is obvious, however, that this form of boiler 
adds greatly to the area of the water surface 
contact, and in that particular is a great improve- 
ment. 



THE STEAM GENERATOR 



27 



The Water Tube Boiler.— In the early days of 
the development of boilers, the nniversal practice 
was to have the products of combustion pass 
through the flues or the tubes. But quick genera- 
tion of steam, and high pressures, necessitated a 




T^ig, 6. Wafer Tule Boiler . Z7nduiew . 

new type. This was accomplished by connecting 
an upper, or steam drum, with a lower, or water 
drum, by a plurality of small tubes, and causing 
the burning fuel to surround these tubes, so that 
the water, in passing upwardly, would thus be 
subjected to the action of the fuel. 



28 MOTORS FOR BOYS 

This form of boiler had two distinct advantages. 
First, an immense surface of water could be pro- 
vided for ; and, second, the water and steam drums 
could be made very small, diametrically, and thus 
permit of very high pressures. 

In Fig. 6, which is designed to show a well 
known type of this structure, A A, represent the 
water drums and B, the steam drum. The wa- 
ter drums are separated from each other, so as 
to provide for the grate bars C, and each water 
drum is connected with the steam drum by a plu- 
rality of tubes D. 

It will thus be seen that a fire box, or combus- 
tion chamber, is formed between the two sets of 
tubes D, and to retain the heat, or confine it as 
closely as possible to the tubes, a jacket E is 
placed around the entire structure. 

The ends of the water and steam drums are 
connected by means of tubes F, shown in side 
view, Fig. 7, for the return or downward flow of 
the water. The diagrams are made as simple as 
possible, to show the principal features only. The 
structure illustrated has been modified in many 
ways, principally in simplifying the construction, 
and in providing means whereby the products of 
combustion may be brought into more intimate 
contact with the water during its passage through 
the structure. 



THE STEAM GENERATOR 



29 



As heretofore stated, this type of boiler is de- 
signed to carry only a small quantity of water, 
so that it is necessary to have practically a con- 
stant inflow of feed water, and to economize in 
this respect the exhaust of the steam engine is 




JF%g. 7. Mater Tufie toiler , - tiidel/iew : 



used to initially heat up the water, and thus, in 
a measure, start the water well on its way to the 
evaporation point before it reaches the boiler. 

Various Boiler Types. — The different uses have 
brought forth many kinds of boilers, in order to 



30 MOTORS FOR BOYS 

adapt them for some particular need. It would 
be needless to illustrate them, but to show the di- 
versity of structures, we may refer to some of 
them by their characteristics. 

Compound Steam-Boiler. — This is a battery of 
boilers having their steam and water spaces con- 
nected, and acting together to supply steam to a 
heating apparatus or a steam engine. These are 
also made by combining two or more boilers and 
using them as a feed water heater or a super- 
heater, for facilitating the production of steam, 
or to be used for superheating steam. 

The terms feed water heater and super heater 
are explained in chapter III. 

Locomotive Steam-Boiler. — This is a tubular 
boiler which has a contained furnace and ash pit, 
and in which the gases of combustion pass from 
the furnace directly into the horizontal interior 
tubes, and after passing through the tubes are 
conveyed directly into the smoke box at the oppo- 
site ends of the tubes. The name is derived from 
the use of such boilers on locomotive engines, but 
it is typical in its application to all boilers hav- 
ing the construction described, and used for gen- 
erating steam. 

Vertical Steam-Boiler. — This is a form of con- 
struction in which the shell, or both the shell and 
the tubes, are vertical, and the tubes themselves 



THE STEAM GENERATOR 31 

may be used to convey the products of combus- 
tion, or serve as the means for conveying water 
through them, as in the well known water tube 
type. 

This form of boiler is frequently used to good 
advantage where it is desired to utilize ground 
space, and where there is sufficient head room. 
Properly constructed, it is economical as a steam 
generator. 

From the foregoing it will be seen that the 
structural features of all boilers are so arranged 
as to provide for the exposure of the largest pos- 
sible area of water to a heated surface so that the 
greatest amount of heat from the fuel may be ab- 
sorbed. 



CHAPTER III 

STEAM ENGINES 

The first steam engine was an exceedingly sim- 
ple affair. It had neither eccentric, cylinder, 
crank, nor valves, and it did not depend upon the 
pressure of the steam acting against a piston to 
drive it back and forth, because it had no piston. 

It is one of the remarkable things in the history 
and development of mechanism, that in this day 
of perfected steam engines, the inventors of our 
time should go back and utilize the principles em- 
ployed in the first recorded steam engine, namely, 
the turbine. Instead of pressure exerting a force 
against a piston, as in the reciprocating engine, 
the steam acted by impacting against a moving 
surface, and by obtaining more or less reaction 
from air-resistance against a freely discharging 
steam jet or jets. 

The original engine, so far as we have any 
knowledge, had but one moving part, namely, a 
vertical tubular stem, to which was attached a 
cross or a horizontal tube. 

The Oeiginal Engine. — Figure 8 is a side view 

32 



STEAM ENGINES 



33 



of the original engine. The vertical stem A is 
pivoted to a frame B, and has a bore C which 
leads up to a cross tube D. The ends of the 
tube D are bent in opposite directions, as shown 
in the horizontal section, Fig. 9. 



-vi 



^ 



3<- 



T^ig. 6. The Original Engine. 




jP^tg. 9. /for iz onto! 6eciicn o fTiibe . 



Steam enters the vertical stem by means of a 
pipe, and as it rushes up and out through the lat- 
eral tubes D, it strikes the angles E at the dis- 
charge ends, so that an impulse is given which 
drives the ends of the tube in opposite directions. 



34 MOTORS FOR BOYS 

As the fluid emerges from the ends of the tubes, it 
expands, and on contacting with the air, the latter, 
to a certain extent, resists the expansion, and this 
reacts on the tube. Thus, both forces, namely, 
impact and reaction, serve to give a turning mo- 
tion to the turbine. 

The Reciprocating Engine. — The invention of 
this type of engine is wrapped in mystery. It has 
been attributed to several. The English maintain 
that it was the invention of the Marquis of Wor- 
cester, who published an account of such an en- 
gine about 1650. The French claim is that Papin 
discovered and applied the principle before the 
year 1680. 

In fact, the first actual working steam engine 
was invented and constructed by an Englishman, 
Captain Savery, who obtained a patent for it in 
1698. This engine was so constructed as to raise 
water by the expansion and condensation of 
steam, and most engines of early times were de- 
voted solely to the task of raising water, or were 
employed in mines. 

Atmospheric Engines. — When we examine them 
it is difficult to see how we can designate them as 
steam engines. The steam did not do the actual 
work, but a vacuum was depended on for the en- 
ergy developed by the atmospheric pressure. 

A diagram is given, Fig. 10, showing how en- 



STEAM ENGINES 



35 



gines of this character were made and operated. 
A working beam A was mounted on a standard 
B, and one end had a chain C on which was 
placed heavy weights D. Near this end was 
also attached the upper end of a rod E, which 
extended down to a pump. 




TtyJO. titeam 



The other end of the working beam had a chain 
F, which supported a piston G working within 
a vertically-disposed cylinder H. This cylinder 
was located directly above a boiler I, and a pipe 
J, with a valve therein, was designed to supply 
steam to the lower end of the cylinder. 

A water tank K was also mounted at a point 



36 MOTORS FOR BOYS 

above the cylinder, and this was supplied with 
water from the pump through a pipe L. An- 
other pipe M from the tank conducted water 
from the tank to the bottom of the cylinder. 

The operation of the mechanism was as fol- 
lows: The steam cock N, in the short pipe J, 
was opened to admit steam to the cylinder, below 
the piston. The stem of the steam cock also 
turned the cock in the water pipe M, so that dur- 
ing the time the steam was admitted the water 
was shut off. 

When the steam was admitted so that it filled 
the space below the piston, the cock N was 
turned to shut off the steam, and in shutting off 
the steam, water was also admitted. The injec- 
tion of water at once condensed the steam within 
the cylinder so a partial vacuum was formed. 

It will be remembered that as steam expanded 
1700 times, the condensation back into water made 
a very rarified area within the cylinder, and the 
result was that the piston was drawn down, thus 
raising both the weight D and also the pump rod 
E. This operation was repeated over and over, 
so long as the cock N was turned. 

The turning of the stem of this cock was per- 
formed manually, — that is, it had to be done by 
hand, and boys were usually employed for doing 
this. When, later on, some bright genius discov- 



STEAM ENGINES 37 

ered that the valve could be turned by the ma- 
chinery itself, it was regarded as a most wonder- 
ful advance. 

The discovery of this useful function has been 
attributed to Watt. Of this there is no conclusive 
proof. The great addition and improvements 
made by Watt, and which so greatly simplified and 
perfected the engine, were through the addition 
of a separate condenser and air pump, and on 
these improvements his fame rests. 

From the foregoing it will be seen that the 
weight D caused the piston to travel upwardly, 
and not the force of the steam, and the suction 
produced by the vacuum within the cylinder did 
the work of actuating the pump piston, so that it 
drew up the water. 

The Piston. — From this crude attempt to use 
steam came the next step, in which the steam was 
actually used to move the piston back and forth 
and thus actually do the work. In doing so the 
ponderous walking beam was dispensed with, and 
while, for a long period the pistons were verti- 
cally-placed, in time a single cylinder was used, 
and a crank employed to convert the reciprocating 
into a circular motion. 

Fig. 11 shows a simple diagram of a steam en- 
gine, so arranged that the operation of the valves 
may be readily understood. The cylinder A has 



38 



MOTORS FOR BOYS 



a steam chest B, which contains therein a slide- 
valve C to cover the ports at the ends of the 
cylinder. This figure shows the crank turning to 
the right, and the eccentric D on the engine shaft 
is so placed, that while the crank E is turning 
past the dead center, from 1 to 2, the slide valve 




^ig. /J. dimp le Ubii/e 7koUo?i . TYrat - position . 




7^1$. ?&.4imple, Value Tnotton . 4er.ondrx>6itior> . 

C is moved to the position shown in Fig. 12, 
thereby covering port F and opening port G. 

It will be seen that the slide valve is hollowed 
within, as at H, and that the exhaust port I leads 
from this hollowed portion while the live steam 



STEAM ENGINES 39 

from the boiler enters through pipe J and tills 
the space K of the chest. 

In Fig. 11 live steam has been entering port 
F, thus driving the piston to the right. At the 
same time the exhaust steam at the right side of 
the piston is discharging through the port G and 
entering the hollow space within the slide valve. 
In Fig. 12 the conditions are reversed, and now 
live steam enters port G, and the exhaust passes 
out through port F. 

When the engine crank reaches the point 3, 
which is directly opposite 1, the reverse action 
takes place with the slide valve, and it is again 
moved to its original position, shown in Fig. 12. 

Importance of the Valve. — Every improve- 
ment which has been made in the engine has been 
directed to the valve. The importance of this 
should be fully understood. As the eccentric is 
constantly turning it is a difficult matter to so ar- 
range the valve as to open or close it at the cor- 
rect time, absolutely, and many devices have been 
resorted to to accomplish this. 

Expanding the Steam. — As all improvements 
were in the direction of economizing the use of 
steam, it was early appreciated that it would be 
a waste to permit the steam to enter the cylinder 
during the entire period that the engine traveled 
from end to end, so that the valve had to be con- 



40 MOTORS FOR BOYS 

structed in such a way that while it would cut off 
the admission of steam at half or three-quarters 
stroke, the exhaust would remain on until the en- 
tire stroke was completed. 

Some engines do this with a fair degree of ac- 
curacy, but many of them were too complicated 
for general use. In the form of slide valve shown 
the pressure of the steam on the upper side, which 
is constant at all times, produces a great wearing 
action on its seat. This necessitated the design- 
ing of a type of valve which would have a firm 
bearing and be steam tight without grinding. 

Balanced Valve. — One of the inventions for 
this purpose is a valve so balanced by the steam 
pressure that but little wear results. This has 
been the subject of many patents. Another type 
also largely used in engines is known as the oscil- 
lating valve, which is cylindrical or conical in its 
structure, and which revolves through less than a 
complete revolution in opening and closing the 
ports. 

Rotary Valve. — The rotary valve, which con- 
stantly turns, is employed where low pressures 
are used, but it is not effectual with high pres- 
sures. This is also cylindrical in its structure, 
and has one or more ports through it, which co- 
incide with the ports through the walls of the en- 
gine, v as it turns, and thus opens the port for ad- 



STEAM ENGINES 41 

mitting live steam and closing the discharge port 
at the same time or at a later period in its rota- 
tion. 

Engine Accessories. — While the steam engine 
is merely a device for utilizing the expansive 
force of steam, and thus push a cylinder back and 
forth, its successful operation, from the stand- 
point of economy, depends on a number of things, 
which are rarely ever heard of except by users 
and engineers. 

Many of these devices are understood only by 
those who have given the matter thorough study 
and application. To the layman, or the ordinary 
user, they are, apparently, worth but little con- 
sideration. They are the things, however, which 
have more than doubled the value of the steam 
engine as a motor. 

Efficiency of Engines. — When it is under- 
stood that with all the refinements referred to the 
actual efficiency of a steam engine is less than 
30 per cent, some idea may be gained of the value 
which the various improvements have added to 
the motor. 

Efficiency refers to the relative amount of power 
which is obtained from the burning fuel. For 
instance, in burning petroleum about 14,000 heat 
units are developed from each pound. If this is 
used to evaporate water, and the steam therefrom 



42 



MOTORS FOE BOYS 



drives an engine, less than 4200 heat units are 
actually utilized, the remaining 9800 heat units 
being lost in the transformation from the fuel to 
power. 

The value of considering and providing for 
condensation, compression, superheating, re-heat- 
ing, compounding, and radiation, and to properly 
arrange the clearance spaces, the steam jackets, 
the valve adjustments, the sizes of the ports and 



y/^ 






//*- 



tf* 



O 1 2 3 4 X f 6 7 

Pre66u?e6->/o,ooo 4doo £7oo /feo 1600 Jbo /bo 



passages, and the governor, all form parts of the 
knowledge which must be gained and utilized. 

How Steam Acts in a Cylinder. — Reference 
has been made to the practice of cutting off steam 
before the piston has made a full stroke, and per- 
mitting the expansive power of the steam to drive 
the piston the rest of the way, needs some ex- 
planation. 

As stated in a preceding chapter the work done 



STEAM ENGINES 43 

is estimated in foot pounds. For the purpose of 
more easily comprehending the manner in which 
the steam acts, and the value obtained by expan- 
sion, let us take a cylinder, such as is shown in 
Fig. 13, and assume that it has a stroke of four 
feet. Let the cylinder have a diameter of a little 
less than one foot, so that by using steam at fifty 
pounds pressure on every square inch of surface, 
we shall have a pressure of about 5000 pounds 
on the piston with live steam from the boiler. 

In the diagram the piston moves forwardly to 
the right from to 1, which represents a distance 
of one foot, so that the full pressure of the steam 
of the boiler, representing 5000 pounds, is ex- 
erted on the piston. At 1 the steam is cut off, 
and the piston is now permitted to continue the 
stroke through the remaining three feet by the 
action of the steam within the cylinder, the ex- 
pansive force alone being depended on. 

As the pressure of the steam within the cylin- 
der is now much less and decreases as the piston 
moves along, we have taken a theoretical indica- 
tion of the combined pressure at each six inch of 
the travel of the piston. The result is that we 
have the following figures, namely, 4000, 2700, 
1750, 1000, 450 and 100. The sum of these figures 
is 10,000 pounds. 

The piston, in moving from to 1, moved one 



44 MOTORS FOR BOYS 

foot, we will say, in one second of time, hence the 
work done by the direct boiler pressure was 5000 
foot pounds; and since the piston was moved 
three feet more by the expansion of the steam 
only, after the steam pressure was shut off, the 
work done in the three seconds required to move 
the piston, was an additional 5000 foot pounds, 
making a total of 10,000 foot pounds for four sec- 
onds, 150,000 foot pounds per minute, or about 45 
horse power. 




2^^. 74. Indicatin g premiere line . 

This movement of the piston to the right, rep- 
resented only a half revolution of the crank, and 
the same thing occurs when the piston moves 
back, to complete the entire revolution. 

Indicating the Engine. — We now come to the 
important part of engine testing, namely, to as- 
certain how much power we have obtained from 
the engine. To do this an indicator card must be 









STEAM ENGINES 



45 



furnished, A card to indicate the pressure, as 
we have shown it in the foregoing diagram would 
look like Fig. 14. 

The essential thing, however, is to learn how 
to take a card from a steam engine cylinder, and 
we shall attempt to make this plain, by a diagram 
of the mechanism so simplified as to be readily un- 
derstood. 




In Fig. 15 we have shown a cylinder A, hav- 
ing within a piston B, and a steam inlet pipe 
C. Above the cylinder is a drum D, mounted on 
a vertical axis, and so geared up with the engine 
shaft that it makes one complete turn with each 
shaft revolution. A sheet of paper E, ruled with 
cross lines, is fixed around the drum. 

The cylinder A has a small vertical cylinder 



46 MOTOES FOR BOYS 

F connected therewith by a pipe A, and in this 
cylinder is a piston H, the stem I of which ex- 
tends up alongside of the drum, and has a pointed 
or pencil J which presses against the paper E. 

Now, when the engine is set in motion the drum 
turns in unison with the engine shaft, and the 
pressure of the steam in the cylinder A, as it 
pushes piston B along, also pushes the piston 
H upwardly, so that the pencil point J traces a 
line on the ruled paper. 

It will be understood that a spring is arranged 
on the stem I in such a manner that it will al- 
ways force the piston H downwardly against the 
pressure of the steam. 

Mean Efficiency. — We must now use a term 
which expresses the thing that is at the bottom 
of all calculations in determining how much power 
is developed. You will note that the pressure on 
the piston during the first foot of its movement 
was 10,000 pounds, but that from the point 1, Fig. 
13, to the end of the cylinder, the pressure con- 
stantly decreased, so that the pressure was not a 
uniform one, but varied. 

Suppose we divide the cylinder into six inch 
spaces, as shown in Fig. 13, then the pressure of 
the steam at the end of each six inches will be the 
figures given at bottom of diagram, the sum total 



STEAM ENGINES 47 

of which is 30,000, and the figures at the lower side 
show that there are eight factors. 

The figure 10,000 represents, of course, two six 
inch spaces in the first foot of travel. 

The result is, that, if we divide the sum total 
of the pressures at the eight points by 8, we will 
get 3750, as the mean pressure of the steam on 
the piston during the full stroke of the piston. 

In referring to the foot pounds in a previous 
paragTaph, it was assumed that the piston moved 
along each foot in one second of time. That was 
done to simplify the statement concerning the use 
of foot pounds, and not to indicate the time that 
the piston actually travels. 

Calculating Hobse Power. — We now have the 
first and most important factor in the problem, — 
that is, how much pressure is exerted against the 
piston at every half revolution of the crank shaft. 
The next factor to be determined is the distance 
that the piston travels in one minute of time. 

This must be calculated in feet. Let us assume 
that the engine turns the crank shaft at a speed 
of 50 revolutions a minute. As the piston trav- 
els 8 feet at each revolution, the total distance 
traveled is 400 feet. 

If, now, we have a constant pressure of 3750 
pounds on the piston, and it moves along at the 



48 MOTORS FOR BOYS 

rate of 400 feet per minute, it is obvious that by 
multiplying these two together, we will get the 
figure which will indicate how many pounds the 
steam has lifted in that time. 

This figure is found to be 1,500,000, which 
means foot pounds, as we have by this means 
measured pressure by feet, or pounds lifted at 
each foot of the movement of the piston. 

As heretofore stated, we must now use the 
value of a horse power, so that we may measure 
the foot pounds by it. If we had a lot of wheat 
in bulk, and we wanted to determine how much 
we had, a bushel measure would be used. So with 
power. The measure, as we have explained, is 
33,000, and 1,500,000 foot pounds should give as 
a result a little over 45 horse power. 
, Condensation. — We now come to the refine- 
ments in engine construction, — that which adds 
so greatly to the economy of operation. The first 
of these is condensation. The first reciprocating 
engine depended on this to do the actual work. 
In this age it is depended upon simply as an aid. 

The first thing however that the engineer tries 
to do is to prevent condensation. This is done 
by jacketing the outside of the cylinder with some 
material which will prevent radiation of heat, or 
protect the steam within from being turned back 



STEAM ENGINES 49 

into water by the cool air striking the outside of 
the cylinder. 

Atmospheric Pressure. — On the other hand, 
there is a time when condensation can be made 
available. The pressure of air on every square 
inch of surface is 14% pounds. When a piston 
moves along and steam is being exhausted from 
the cylinder, it must act against a pressure of 
14% pounds on every square inch of its surface. 

The problem now is to get rid of that back pres- 
sure, and the old type engines give a hint how 
it may be done. Why not condense the steam dis- 
charged from the engine cylinder? In doing so a 
vacuum is produced on the exhaust side of the 
piston, at the same time a pressure is exerted on 
its other side. 

The Condenser. — Thus the condenser is 
brought into existence, as an aid. By jacketing 
condensation is prevented; it is fought as an 
enemy. It is also utilized as a friend. It is so 
with many of the forces of nature, where man 
for years vainly fought some principle, only to 
find, later on, that a friend is more valuable than 
a foe, and to utilize a material agency in nature 
is more economical than to fight it. 

Pre-heating. — The condenser does two things, 
both of which are of great value to the economical 



50 MOTORS FOR BOYS 

operation of the engine. For the purpose of rap- 
idly converting the steam back into water as it 
issues from the engine cylinder, water is used. 
The steam from the cylinder has a temperature 
of 212 degrees and upwards, dependent on its 
pressure. 

Water, ordinarily, has a temperature of 70 de- 
grees, or less, so that when the steam strikes a 
surface which is cooled down by the water, it is 
converted back into liquid form, but at a tempera- 
ture less than boiling water. The water thus con- 
verted back from the steam gives up part of its 
heat to the water which cools the condenser, and 
the water from the condenser, as well as the water 
used to cool the condenser, are thus made avail- 
able to be fed into the boiler, and thus assist in 
again converting it into a steam. 

The economy thus lies in helping the coal, or 
other fuel, do its work, or, to put it more specifi- 
cally, it conserves the heat previously put out by 
the coal, and thus saves by using part of the heat 
over again. 

Superheaters. — Another refinement, and one 
which goes to the very essence of a heat motor, 
is the method of superheating the steam. This 
is a device located between the boiler and the en- 
gine, so that the steam, in its transit from the 
boiler to the engine, will be heated up to a high 



STEAM ENGINES 51 

degree, and in the doing of which the pressure 
may be doubled, or wonderfully increased. 

This may be done in an economical manner in 
various ways, but the usual practice is to take 
advantage of the exhaust gases of the boiler, in 
the doing of which none of the heat is taken from 
the water in the boiler. 

The products of combustion escaping from the 
stacks of boilers vary. Sometimes the tempera- 
ture will be 800 degrees and over, so that if pipes 
are placed within the path of the heated gases, 
and the supply steam from the boiler permitted to 
pass through them a large amount of heat is im- 
parted to the steam from a source which is of no 
further use to the water being generated in the 
boiler. 

Compounding. — When reference was made to 
the condensation of steam as it issued from the 
boiler, no allusion was made to the pressure at 
which it emerged. If the cylinder was well jack- 
eted, so that the amount of condensation in the 
cylinder was small, then the pressure would still 
be considerable at the exhaust. Or, the steam 
might be cut off before the piston had traveled 
very far at each stroke, in which case the exhaust 
would be very weak. 

In practice it has been found to be most 
economical to provide a high boiler pressure, and 



52 MOTORS FOR BOYS 

also to superheat the steam, but where it is not 
superheated, and a comparatively high boiler 
pressure is provided, compounding is resorted 
to. 

To compound steam means to use the exhaust 
to drive a piston. In such a case two cylinders 
are placed side by side, one, called the high pres- 
sure cylinder, being smaller than the low pressure 
cylinder, which takes the exhaust from the high 
pressure. 

The exhaust from the second, or low pressure 
cylinder may then be supplied to a condenser, and 
in that case the mechanism would be termed a 
compound condensing engine. If a condenser is 
not used, then it is simply a compound engine. 

Triple and Quadruple Expansion Engines. — 
Instead of using two cylinders, three, or four, are 
employed, each succeeding cylinder being larger 
than the last. As steam expands it loses its pres- 
sure, or, stated in another way, whenever it loses 
pressure it increases in volume. For that rea- 
son when steam enters the first cylinder at a pres- 
sure of say 250 pounds, it may exhaust there- 
from into the next cylinder at a pressure of 175 
pounds, with a corresponding increase in volume. 

To receive this increased volume, without caus- 
ing a sensible back pressure on the first cylinder, 
the second cylinder must be larger in area than 



STEAM ENGINES 



53 



the first; in like manner when it issues from the 
exhaust of the second cylinder at 125 pounds pres- 
sure, there is again an increase in volume, and so 
on. 

Examine Fig. 16, which shows a pair of cylin- 
ders, A being the high, and B the low pressure 
cylinders, the exhausts of the high pressure be- 




E Open. 3 0" Cloded 

J^iff.JC. Compound 2?n gine . 

ing connected up with the inlets of the low pres- 
sure, as indicated by the pipes, C D. 

The diagram does not show the valve opera- 
tions in detail, it being sufficient to explain that 
when the valve E in the pipe C is closed, the valve 
F, at the other end of the cylinders, in the pipe 
D, is closed. The same principle is employed in 
the triple and quadruple expansion engines, 
whereby the force of the steam at each exhaust is 
put to work immediately in the next cylinder, until 



54 



MOTORS FOR BOYS 



it reaches such a low pressure that condensation 
is more effective than its pressure. 

The diagram, as given, is merely theoretical, 
and it shows the following factors : 

First : The diameter of each piston. 

Second: The area of each piston in square 
inches. 



JDiameter/2 in. 




266 JM. 






Dia?7teter f4 in.. 
stream. p?e66we 





Jliamete?- J6%> in. 
s6feam p?€66ure 
/gQlfo. 








3iwnefer£Oi?i. 

aom. 





cAiva o n>i6ton 708 sain. 
Piston pretewv 
£7ogolM 

c/Jrea oF pi&ton &7§$ig, 
Pidton pre66u?e 
£6460 Ifo . 

rfrea cF pid ion /OS 4y. VI 
2588Q ZH . 



direc t, of pi6ion 3006#/n. 
Ptetion pre6$u7e 
£ J ,000 Ifo. 



Third: The steam pressure in each cylinder. 

Fourth: The piston pressure of each cylinder. 

It will be seen that an engine so arranged is 
able to get substantially the same pressure in 
each of the second, third and fourth cylinders, 
as in the first (see Fig. 16a), and by condensing 
the discharge from the fourth cylinder a most 
economical use of steam is provided for. 



STEAM ENGINES 55 

The Steam Turbine. — We must now consider 
an entirely new use of steam as a motive power. 
Heretofore we have been considering steam as a 
matter of pressure only, in the development of 
power. It has been observed that when the pres- 
sure of steam decreases at the same temperature 
it is because it has a greater volume, or a greater 
volume results. 

When steam issues from the end of a pipe its 
velocity depends on its pressure. The higher the 
pressure the greater its velocity. The elastic 



jfL 



/ 2 <3 <4 h tf 

l^tg. 17. Cha?iging Ih-eS&itre to/o l/e?bci fy 

character of steam is shown by its action when 
ejected from the end of a pipe, by the gradually 
enlarging area of the discharging column. 

In a reciprocating engine the power is derived 
from the pressure of the steam; in a turbine the 
power results from the impact force of the steam 
jet. Such being the case velocity in the move- 
ment of the steam is of first importance. 

Pressure and Velocity. — To show the effective- 
ness of velocity, as compared with pressure, ex- 
amine Fig. 17. A is a pipe discharging steam at 
a pressure of 100 pounds. To hold the steam in 



56 MOTOES FOR BOYS 

the pipe would require a pressure of 100 pounds 
against the disk B, when held at 1, the first posi- 
tion. 

Suppose, now, the disk is moved away from the 
end of the pipe to position 2. The steam, in issu- 
ing forth, strikes the disk over a larger area, and 
in escaping it expands, with the result that its 
velocity from 1 to 2 is greater than the movement 
of the steam within the pipe that same distance. 

The disk is now moved successively to posi- 
es tc 



J^ig. W. Reaction a vczznat Jfir . 



Z^ig. S<9. Reaction a, oa,i7t6t Surface . 

tions 3, 4, 5, and so on. If we had a measuring 
device to determine the push against the disk at 
the various positions, it would be found that there 
is a point at some distance from the end of the 
pipe, at which the steam has the greatest strik- 
ing force, which might be called the focal point. 
A blow pipe exhibits this same phase ; the hot- 
test point is not at the end of the pipe, but at an 
area some distance away, called the focal point 
of heat. 



STEAM ENGINES 



57 



The first feature of value, therefore, is to un- 
derstand that pressure can be converted into 
velocity, and that to get a great impact force, 
the steam must be made to strike the hardest and 
most effective blow. 

When a jet of steam strikes a surface it 
is diverted or it glances in a direction opposite 
the angle at which it strikes the object. In 
directing a jet against the blades of a turbine it 
is impossible to make it strike squarely against 
the surface. 



J^ig. 20. Ta?bin& < 6fraig7iir filadeA . 

Let us assume that a wheel A, Fig. 20, has a set 
of blades B, and a steam jet is directed against 
it by the pipe C. It will be seen that after the 
first impact the steam is forced across the blades, 
and no further force is transferred to them. 

Form of Blades. — The blades are therefore so 
curved, that the steam after the first impact can- 
not freely pass along the blade, as it does on a 
straight blade, but imparts on every element of 
the curved-back blade, thereby giving up continu- 
ally part of its speed to the blade. 



58 



MOTORS FOR BOYS 



This is clearly shown in Fig. 21, where the 
pipe D ejects the stream of steam against the 
concaved blades B. Many modifications have 
been made in the shapes of these blades, all de- 
signed to take advantage of this action. 

Compounding the Jet. — We may extend the ad- 
vantages gained by this form of blades, and di- 




T^ig. 21. CurirzcL 3laclc6 . 



j> t J ; ; ; J ; t 

* \ A V X X \ \\ 

2^1$. 22. Compound Turbine . 

verting the course of the jet, so that it will be 
directed through a series of wheels, each of which 
will get the benefit of the moving mass from the 
pipes. 

Such a structure is shown in Fig. 22, in which 
three bladed wheels A, B, C, are caused to rotate, 
a set of stationary blades D, E, being placed be- 
tween the three moving wheels, but the stationary 



STEAM ENGINES 59 

blades are disposed in reverse directions. When 
the steam from pipes F, F, impinges against the 
blades of the first wheel A, it is directed by the 
stationary blade D> to the next wheel B, and from 
the stationary blade E to the blades of the next 
wheel C, thus, in a manner somewhat similar to 
the compounding effect of the steam engine, 
utilizes the pressure which is not used at the first 
impulse. 



CHAPTEE IV 

FUELS AND COMBUSTION 

All fuels must be put into a gaseous state be- 
fore they will burn. This is true of coal as well 
as of hydro-carbon oils. 

Neither coal nor petroleum will burn in its na- 
tive state, without the addition of oxygen. This 
is absolutely necessary to support combustion. 
Burning is caused by the chemical union of oxygen 
with such substances as will burn. 

This burning process may be slow, and extend 
over a period of years, or it may be instantaneous, 
in which latter case the expansion of the heated 
gases is so great as to cause an explosion. When 
a sufficient amount of oxygen has been mixed with 
a fuel to permit it to burn, a high temperature is 
necessary to cause the immediate burning of the 
entire mass. 

If such a temperature is not present the course 
of combustion is not arrested, but it will, on its 
own account, start to oxydize, and eventually be 
reduced to the same condition that would take 
place if exploded by means of a flame. 

60 



FUELS AND COMBUSTION 61 

Solid Fuels. — The great fuels in nature are 
carbon and hydrogen, carbon being the substance 
most widely known and depended upon. Hard 
coal, for instance, is composed almost wholly of 
carbon ; whereas soft coal has a considerable quan- 
tity of hydrogen. 

As coal was formed by wood, which, through 
long process of time became carbonized, it con- 
tains considerable foreign matter which will not 
burn, forming ash. 

Liquid Fuels. The volatile oils, however, have 
very little non-combustible matter. Ordinary 
petroleum contains about 80 per cent, of carbon, 
and from 12 to 15 per cent, of hydrogen, the 
residue being foreign matter, all more or less 
susceptible of being consumed at high tempera- 
tures. 

Combustion. The term combustion, in its gen- 
eral sense, means the act of burning; but in a 
larger and more correct application it refers to 
that change which takes place in matter when 
oxygen unites with it. 

Oxygen is a wonderful element, and will unite 
with all known substances, unlike all other ele- 
ments in this respect. It may take years for it 
to form a complete unity. Thus, wood, in time, 
will crumble, or rot, as it is called. This is a 
slow process of combustion, brought about with- 



62 MOTORS FOR BOYS 

out applying heat to it, the change taking place 
in a gradual way, because oxygen unites with only 
a small portion of the wood. 

Oxidation. — Iron will rust. This is another in- 
stance of combustion, called oxidation. When 
oxygen unites with a substance it may produce an 
acid, or an alkali, or a neutral compound. When 
wood is burned it produces an ash, and this ash 
contains a large amount of potash, or lye, which 
is an alkali, or a salt. So when other substances 
are burnt the result may be an acid, like sulphur, 
or it may be unlike either acid or the alkali. 

The unity of oxygen with the food in the body 
is another instance of oxidation, which produces 
and maintains the heat necessary for existence. 

Carbon or hydrogen, as a fuel, are inert with- 
out oxygen, so that in considering the evolution 
of a force which is dependent on heat, we should 
know something of its nature, thereby enabling 
us to utilize it to the best advantage. 

The Hydro-carbon Gases — If petroleum, or 
gasoline, should be put into the form of a gas, 
and as such be confined in a receiver, without add- 
ing any oxygen, it would be impossible to ignite it. 

The character of the material is such that it 
would instantaneously extinguish any flame. 
Now, to make a burning mixture, at least three 



FUELS AND COMBUSTION 63 

parts of oxygen must be mixed with one of the 
hydro-carbon, before it is combustible. 

Oxygen and Atmosphere. — The atmosphere is 
not oxygen. Only one-fifth of common air is 
oxygen, the residue being, principally, nitrogen, 
which is not a fuel. To produce the proper aera- 
tion, therefore, at least fifteen parts of air must 
be mixed with one part of hydro-carbon gas. 

The term hydro-carbon is applied to petroleum, 
and its products, because the elements carbon and 
hydrogen make up the largest part of the oil, 
whereas this is not the case with most of the other 
oils. 

We are now dealing with a fuel such as is 
needed in Internal Combustion Engines, and it is 
well to know some of the problems involved in 
the use of the fuel, as this will give a better un- 
derstanding of the structure of the devices which 
handle and evolve the gases, and properly burn 
them within the engine. 

Vaporizing Fuel. — As the pure liquid will not 
burn in that state the first essential is to put it 
into a gaseous form, or to generate a vapor from 
it. The vapor thus made is not a gas, in the true 
sense of that term, but it is composed of minute 
globules of finely-divided particles of oil. 

Nearly all liquids will vaporize if permitted to 



64 MOTORS FOR BOYS 

come into contact with air. The greater the 
surface exposed to air the more rapidly will it 
turn into a vapor. 

By forcibly ejecting the liquid from a pipe or 
spraying device, and mingling air with it, evapora- 
tion is facilitated, and at the same time the proper 
admixture of air is provided to make a combus- 
tible substance the moment sufficient heat is 
brought into contact with it. 

This is what actually takes place in a gasoline 
engine, and all the mechanism is built with this 
end in view. 

It has been the universal practice to make an ex- 
plosive mixture of this character, and then ignite 
it by means of an electric spark, but it is now 
known that such a fuel can be exploded by pres- 
sure, and this needs some explanation. 

Explosion by Compkession. — The study of the 
compressibility of gases is an interesting one. 
As we have previously stated, the atoms, compris- 
ing the gases, are constantly moving among them- 
selves with great rapidity, so that they bombard 
the sides of the receiver in which they are con- 
fined, and also contact with each other in their 
restless movements. 

When compression takes place the speed of 
the movements of the atoms is greatly accelerated, 



FUELS AND COMBUSTION 65 

the friction of their movements is increased, and 
heat is evolved. As the pressure becomes 
greater the heat increases until it is of such in- 
tensity that the gas ignites, and an explosion fol- 
lows. 

How Compression Heats. — The theory of the 
compressibility of gases may be stated as follows : 
Let us assume that the temperature of the air is 
70 degrees Fahrenheit, and we have a receiver 
which holds two cubic feet of this air. 

If the contained air is now compressed to a 
volume of one cubic foot, the temperature of two 
cubic feet is compressed into one cubic foot, and 
there is now 140 degrees of heat within the 
receiver. 

If this cubic foot of air is again compressed to 
half its volume, the temperature is correspond- 
ingly increased. "While this it not absolutely true 
in practice, owing to the immense loss caused by 
radiation, still, it will enable the mind to grasp 
the significance of compression, when the subject 
of heat is concerned. 

Elasticity of Gases. — The great elasticity of 
gases, and the perfected mechanical devices for 
compressing the same, afford means whereby ten 
or twenty atmospheres can be forced into a re- 
ceiver, and thereby produce pressures of several 



66 MOTORS FOR BOYS 

hundred pounds, which would mean sufficiently 
high temperatures to ignite oils having the higher 
flash point. 

Advantages of Compression. — The compression 
system permits of the introduction of a larger 
quantity of fuel than is usually drawn into the cyl- 
inder, and thereby a greater and more efficient ac- 
tion is produced on the piston of the engine on ac- 
count of quicker combustion and therefore higher 
gas pressures. 

The compression, however, rarely if ever ex- 
ceeds six atmospheres or about 90 pounds per 
square inch. 

The Necessity of Compression. — There are two 
reasons why compression is necessary before ig- 
niting it. First, because it is essential to put suf- 
ficient gas in the cylinder to make the engine effi- 
cient. 

To illustrate : Suppose we have a cylinder ca- 
pable of drawing in 150 cubic inches of gas, and 
this is compressed down to 25 cubic inches, the 
space then occupied by the gas would represent 
what is called the clearance space at the head of 
the cylinder. To compress it to a greater degree 
the clearance space might be made smaller, which 
could be done in several ways, but whether the 
gas thus drawn in should be compressed to 30, 
or 25, or even 10 cubic inches, it is obvious that 



FUELS AND COMBUSTION 67 

there would be no more fuel in the cylinder in one 
case than in the other. As however the mean ef- 
fective pressure, which determines the efficiency 
of the motor, increases with the compression pres- 
sure, the latter should be as high as possible, but 
not so high that premature explosion takes place 
owing to the heat created by compression. 

Second: The more perfect the mixture of the 
vaporized product with the air, the more vigorous 
will be the explosion. The downward movement 
of the piston draws in the charge of air and 
sprayed jet of gasoline, and the only time for mix- 
ing it is during the period that it travels from the 
carbureter through the pipes and manifold to the 
cylinder. 

Having in mind the statement formerly made 
that compression causes a more rapid movement 
of the molecules of a gas, it is obvious that the 
upward movement of the piston, in the act of 
compressing the gas has a more positive action 
in causing an intimate mixture of the hydro-car- 
bon gases than took place when the gases were 
traveling through the pipes on their way to the 
cylinder. 



CHAPTER V 

THE INTEKNAL COMBUSTION ENGINE 

It will be observed that in a steam engine tbe 
heat is developed outside of the cylinders and 
the latter used solely for the purpose of taking the 
steam and utilizing it, by causing its expansion to 
push a piston to and fro. 

We shall now consider that type of motor which 
creates the heat within the cylinder itself and 
causes an expansion which is at once used and 
discharged at the reciprocating motion of the pis- 
ton. 

The original method of utilizing what is called 
Internal combustion Motors, was to employ a fixed 
gas. A fixed gas is one which will remain per- 
manently in that condition, unlike a vapor made 
from gasoline. The difference may be explained 
as follows: 

Fixed Gases. — If the vapor of gasoline, or 
petroleum, is subjected to a high heat, upwards of 
1500 degrees, it is so changed chemically, that it 
will not again return to a liquid state. This is 
called fixing it. Gas is made in that way from the 

68 



INTERNAL COMBUSTION ENGINE 69 

vapor of coal, and fixed, producing what is called 
illuminating gas. 

Although the temperature of fixing it is fully 
three times greater than is required to explode 
it, the fact that it is heated in closed retorts, 
and oxygen is prevented from mixing with it, pre- 
vents it from burning, or exploding. 

Gas Engines. — Such a gas has been used for 
many years in engines which were usually of the 
horizontal type, and were made exceedingly heavy 
and cumbrous, and provided with enormous fly 
wheels. Gases thus made are not as rich as those 
generated direct from the hydro-carbon fuels, be- 
cause, being usually made from coal they did not 
have a large percentage of hydrogen. 

Energy of Carbon and Hydrogen. — When a 
pound of carbon is burned, it develops 14,500 
heat units, and a pound of hydrogen over 52,000 
heat units. Assuming that 85 per cent, of a pound 
of petroleum is carbon, and 15 per cent, is hydro- 
gen, the heat units of the carbon would be 12,225, 
and the heat units of the 15 per cent, of hydrogen 
would be 12,800. The combined value is, there- 
fore, 25,025, which is almost double that of coal 
gas. 

This fact makes the gasoline engine so much 
more efficient, and for the same horse power the 



70 MOTORS FOR BOYS 

cylinders can be made smaller, and the whole 
structure much lighter in every way. 

Gasoline motors are of two types, one in which 
an explosion takes place at every revolution of 
the crank, called the two-cycle, and the other the 
four-cycle, in which the explosion occurs at every 
other turn of the crank. 

The terms two-cycle is derived from the move- 
ment of the piston, as that moves downwardly 
during the period when the crank is making a half 
turn, and returns in its upward stroke when the 
crank completes the turn, or that two half turns 
of the crankshaft complete the cycle. Four-cycle 
engines have two such complete movements at 
each impulse, or require four half turns of the 
crankshaft to complete the cycle. 

The Two-Cycle Type. — In order to clearly dis- 
tinguish between this and the four-cycle, it would 
be well to examine the diagram, Fig. 23. For a 
clearer understanding the drawing is explained 
in detail. 

The cylinder A, within which the piston works, 
has a removable cap B, and at its lower end a re- 
movable crank case C. The case is designed to 
entirely close the lower end of the cylinder so that 
it is air tight, for reasons which will be explained. 

The outer jacket, or casing D, at the upper end 
of the cylinder, is designed to provide a space E, 



INTERNAL COMBUSTION ENGINE 71 

for the circulation of water, to cool the cylinder 
during its working period. The crankshaft F 
passes through the crank case, the latter having 
suitable bearings G for taking care of the wear. 




y^tg.^S. Two - cycle. Tlsitit po6iUon . 

The piston H is connected up with the rod I, 
the latter being hinged at a point within the pis- 
ton, as shown. The crank case has an inlet port, 
provided with a valve which opens inwardly, so 



72 MOTORS FOR BOYS 

that when the piston moves upwardly the valve 
will open and air will be drawn into the crank 
case and space below the piston. 

At one side is a vertical duct K, which extends 
from a point directly above the crank case, to such 
a position that when the piston is at its lowest 
point gas can be discharged into the space above 
the piston. 

On the opposite side of the cylinder, and a little 
above the inlet port of the duct K, is a discharge 
port M. The inlet port and the discharge port, 
thus described, are both above the lower end of 
the piston when it is at its highest point. 

The spark plug is shown at N. On the upper 
end of the piston, and close to the side wall 
through which the inlet port K is formed, is an 
upwardly-projecting deflecting plate 0, the uses 
of which will be explained in the description of its 
operation. 

Fig. 23 shows the piston at its highest point, 
and we will now assume that ignition takes place, 
thus driving the piston downwardly until the 
upper end of the piston has fully uncovered the 
discharge port M, as shown in Fig. 24. This per- 
mits the exhaust to commence, and as the piston 
proceeds down still further, so as to uncover the 
inlet port K, the gas, which at the down stroke 
has been compressed in the space below the piston, 



INTERNAL COMBUSTION ENGINE 73 

rushes in, and as it strikes the deflecting plate 
0, is caused to flow upwardly, and thus helps to 
drive out the burnt gases remaining at the upper 
end of the cylinder. 




Ttt/o - c ycle Engine . 
T^ig £4. -decondpo6itio?t . 7^.26. Thii-d position . 

This action is called scavenging the cylinder, 
and the efficiency of this type of engine is largely 
due to the manner in which this is done. It is 
obvious that more or less of the unburnt gases 



74 MOTORS FOR BOYS 

will remain, or that some of the unburnt car- 
bureted air will pass out at each discharge, and 
thus, in either case, detract from the power of 
the subsequent explosion. 

As the piston now moves upwardly to complete 
the cycle, the piston closes both of the ports, thus 
confining the gas which was previously partly 
compressed, and as the piston proceeds the gas 
is still further compressed until the piston again 
reaches the upward limit of its motion. 

Advantages or the Two-Cycle Engine. — This 
kind of engine has several distinct advantages. 
It has less weight than the four-cycle; it gives 
double the number of impulses for a given num- 
ber of revolutions of the crankshaft; and it dis- 
penses with valves, springs, cam-shafts, stems 
and push rods. 

More or less danger, however, attends the 
operation of a two-cycle engine, principally from 
the fact that an explosive mixture in a par- 
tially compressed condition is forced into the 
space which the instant before was occupied by a 
flame, and it is only because the expansion of the 
burst gases at the previous charge has its tem- 
perature decreased so far below the explosion 
point, that the fresh gas is not ignited, although 
there have been occasions when explosions have 
taken place during the upstroke. 



INTERNAL COMBUSTION ENGINE 75 

The Four-Cycle Engine. — The most approved 
type is that which is known as the four-cycle. 
This will also be fully diagrammed so as to enable 
us to point out the distinctive difference. 

Figs. 26 and 27 show sections of a typical four- 
cycle engine, in which the inlet and the exhaust 
valves are mechanically operated. The cylinder 




£j2W~ C#cU \£7ngine. 
2^10. £6. THrdt potitton Twiggy. Second position 

A is either cast with or separate from the crank 
case B, and has a removable head C. The upper 
end of the cylinder has a water space formed by 
the jacket D. 

The inlet port E and the discharge port F are 
both at the upper end of the cylinder. The crank 
shaft G passes horizontally through the crank 



76 MOTORS FOR BOYS 

case, and it is not necessary, as in the case of the 
two-cycle -engine, to have the case closed tight. 

The piston H is attached to the connecting rod 
I, which is coupled to the crank, as shown. The 
crank shaft has a small gear J, which meshes 
with two gears of double size on opposite sides of 
the crank shaft, one of the gears K, being designed 
to carry the cam L for actuating the stem I/, which 





7 r ly./g(g. Third position . TUg.&Q. Fburtt position . 

opens the valve M in the port that admits the car- 
bureted air. 

The other large gear N is mounted on a shaft 
which carries a cam that engages the lower end 
of a push rod P, to open the valve Q in the dis- 
charge port F. It should be observed that the 
stems I/, P, are made in two parts, with interpos- 



INTERNAL COMBUSTION ENGINE 77 

ing springs R, so the valves may be firmly seated 
when the stems drop from the cams. 

The spark plug S is located in the head, close 
to the inlet port. The character of the igniting 
system is immaterial, as the object of the present 
diagrams is to show the cycle and method of 
operating the engine at each explosion, and to 
fully illustrate the manner in which it is distin- 
guished from the two-cycle type. 

A fly wheel is necessary in this as in the other 
type, and in practice the two gear wheels, K, N, 
are placed outside of the case B, and only the 
small gear, and the cam shafts, on which the cams 
are mounted, are within the case. 

The operation is as follows: In Fig. 26 the 
piston is shown in a position about to commence 
its downward movement, and we will assume that 
the ignition has just taken place. Both valves 
M, Q, are closed, as it will be noticed that the cams 
L, 0, are not in contact with the lower ends of 
the push rods. 

The explosion drives the piston down to the 
position shown in Fig. 27, when the cam be- 
gins to raise the stem P, and thus opens the dis- 
charge valve Q, permitting the burnt gases to 
escape as the piston travels upwardly to the 
position shown in Fig. 28. 

At this position the valve Q closes, and the cam 



78 MOTORS FOR BOYS 

L opens the inlet valve M, so that as the piston 
descends the second revolution, the carbureted air 
is drawn in until the crank has just turned at its 
lowest limit of movement, as shown in Fig. 29. 
The upward stroke of the piston now performs 
the work of compressing the carbureted air in 
the cylinder, and it is ready for the ignition the 
moment it again reaches the position shown in 
Fig. 26. 

The Four Cycles. The four distinct opera- 
tions thus performed are as follows: First, the 
explosion, and downward movement of the pis- 
ton. Second, the upward movement of the pis- 
ton, and the discharge of the burnt gases. Third, 
the down stroke of the piston, and the indrawing 
of a fresh charge of carbureted air. Fourth, the 
upward movement of the piston, and the compres- 
sion of the charge of carbureted air. 

The order of the engine performance may be 
designated as follows: 1. Impulse. 2. Ex- 
haust. 3. Admission. 4. Compression. 

Ignition Point. — "While the point of ignition, 
shown in the foregoing diagrams, represents them 
as taking place after the crank has passed the 
dead center, the firing, in practice, is so adjusted 
that the spark flashes before the crank turns past 
the dead center. 

The reason for this will be apparent on a little 



INTERNAL COMBUSTION ENGINE 79 

reflection. As the crank turns very rapidly the 
spark should be advanced, as it is called, because 
it takes an interval of time for the spark to take 
effect and start the explosion. If the sparking 
did not take place until the crank had actually 
passed the- dead center, the full effect of the com- 
pression and subsequent explosion pressure would 
not be had. 

Advantage of the Four-Cycle Type. — The 
most marked advantage in the four-cycle type is 
its efficiency. As it has one full stroke within 
which to exhaust the burnt gases, the cylinder is in 
a proper condition to receive a full value of the 
incoming charge, and there is no liability of any 
of the unburnt gases escaping during the exhaust 
from the previous explosion. 

The next important advantage of this type is 
in the fact that it can be operated at a higher 
speed than the two-cycle type, and this is a great 
advantage, notwithstanding the less number of 
impulses in the four-cycle type. 

The Loss in Power. — The great disadvantage 
in all engines of this class is the great loss re- 
sulting from their action. The explosion which 
takes place raises the temperature to fully 2000 
degrees of heat, and unless some provision is 
made to keep the cylinder down to a much lower 
temperature the engine would soon be useless. 



80 MOTORS FOR BOYS 

High temperatures of this character absolutely 
prevent lubrication, a thing which is necessary to 
insure proper working. For this reason a water 
jacket is provided, although there are engines 
which are cooled by the action of air. 

In any event, the heat imparted to the cylinder 
is carried away and cannot be used effectively, 
so that fully one-half of the power is dissipated 
in this direction alone. 

The next most serious loss is in the escape of 
heat through the burnt gases, which amounts to 
seventeen per cent. If the expansive force of the 
burnt gases at the time of. ignition is 250 pounds 
per square inch, and at the time of the discharge 
it is fifty pounds, only four-fifths of its power 
is effectively used. 

As, however, the discharge is against the air 
pressure of nearly fifteen pounds per square inch, 
it is obvious that thirty-five pounds per inch is 
driven away and lost. 

The third loss is by conduction and radiation, 
which amounts to fifteen per cent, or more, so that 
the total loss from all sources is about eighty- 
four per cent., leaving not more than sixteen per 
cent, of the value of the fuel which is converted 
into power. 

Engine Construction. — In the construction of 
engines the utmost care should be exercised in 



INTERNAL COMBUSTION ENGINE 81 

making the various parts. The particular fea- 
tures which require special care are the valves, 
which should be ground to fit tightly, the proper 
fitting of the piston rings, crank shaft and con- 
necting rod bearings as well as the accurate relin- 
ing of these bearings. 




l^ig.dO. Valife Grinding . 



Valve Grinding. — Fig. 30 shows a valve and 
valve seat. The valve has usually a cross groove 
so that a screw driver in a drill stock may be 
used to turn it and to exert the proper pressure. 
The finest emery powder and a first class quality 
of oil should be used. The valve is seated and 



82 MOTORS FOR BOYS 

after the oil and emery powder are applied the 
drill stock is used to turn the valve. 

After twenty or thirty turns, wipe off the parts 
and examine the contact edges, to see whether 
the entire surfaces are bright, which will indicate 
that the valve fits true on its seat. Never over- 
grind. This is entirely unnecessary. It is better 
also to rock the crank of the drill stock back and 
forth, instead of turning it in one direction only. 

The Crank Shaft. — The crank shaft is the 
most difficult part of the engine to build. It is 
usually made of a single forging of special steel 
and the cranks and bearings are turned out of 
this, requiring the utmost care. Formerly these 
were subject to breakage, but improved methods 
have eliminated all danger in this direction. 

The Cams. — Notwithstanding the ends of the 
push rods are provided with rollers to make the 
contact with the cams, the latter will wear, and 
in doing so they will open the valves too late. 
The slightest wear will make considerable differ- 
ence in the inlet valve, and it requires care and 
attention for this reason, in properly designing 
the cams, so that wear will be brought to a 
minimum. 



CHAPTER VI 

CAEBUEETEBS 

A carbueetee, is a device which receives and 
mixes gasoline and air in proper proportions, and 
in which a vapor is formed for gasoline engines. 

The product of the carbureter is a mixture of 
gasoline vapor and air, not a gas. A gas, as ex- 
plained, is of such a character that it remains 
fixed and will not stratify or condense. 

Functions of a Cabbueeteb. — The function of 
a carbureter is to supply air and gasoline by 
means of its adjustable features so as to make 
the best mixture. The proportions of air and 
gasoline will vary, but generally the average is 
fifteen parts of air to one of gasoline vapor. 

If there is too much gasoline, proportionately, 
a waste of fuel results, as a great amount of soot 
is formed under those conditions. If there is an 
excess of air the mixture, when ignited, will not 
have such a high temperature, hence the expan- 
sive force is less, and the result is a decrease of 
power. 

While it is possible to get a rapid evaporation 

83 



84 MOTORS FOR BOYS 

from gasoline by heating it, experience has shown 
that it is more economical to keep the gasoline 
cool, or at ordinary temperatures, provided the 
carbureter is properly constructed, because the 
vapor, if heated, when drawn into the engine, 
will be unduly expanded, and less fuel in that 
case is drawn in at each charge, and less power 
results. 

Rich Mixtures. — There are conditions under 
which rich mixtures are advantageous. This is a 
mixture in which there is a larger percentage of 
gasoline than is necessary for instantaneous com- 
bustion. For ordinary uses such a mixture would 
not be economical. 

At low speeds, however, or when carrying heavy 
loads, it is desirable, for the reasons that at a 
slow speed the combustion is slower. 

Rich mixtures are objectionable at high speeds 
because, as the combustion is slow, incomplete 
combustion within the power stroke results, the 
temperature of the gas at the end of the stroke is 
very high, and this will seriously affect the ex- 
haust valves. Furthermore, there is likelihood of 
the gas continuing to burn after it is discharged 
from the cylinder. 

Lean Mixtures. — Such a mixture is one which 
has a less amount of gasoline than is necessary 
to make a perfectly explosive compound. For 



CARBURETERS 85 

high speeds a lean mixture is desirable, princi- 
pally because it burns more rapidly than a rich 
mixture. 

Types of Cabbubetebs. — There are two distinct 
types of carbureters, one which sprays the gaso- 
line into a conduit through which air is passing, 
and the other in which a large surface of gasoline 
is placed in the path of the moving air column, 
which was originally used, but has been absolutely 
replaced by the jet carbureters on account of their 
better control features. 

It will be remembered that reference was made 
to the manner in which vaporization takes place, 
this term being used to designate that tendency of 
all liquids to change into a gaseous state. All car- 
bureters are designed with the object of mechan- 
ically presenting the largest possible area of oil 
to the air, so that the latter will become impreg- 
nated with the vapor. 

The Sprayer. — The best known type depends 
on dividing up the gasoline into fine globules, by 
ejecting it from a small pipe or jet. The spray 
thus formed is caught by the air column produced 
by the suction of the engine pistons, and during 
its passage through the throttle and the manifold, 
is in condition where a fair mixture of air and 
vapor is formed, which will readily ignite. 

The Surface Type. — This form of carbureter 



86 MOTORS FOR BOYS 

provides a pool of gasoline with a large surface, 
within the shell,, so arranged that as the air is 
drawn past the pool it must come into contact 
with the oil, and thus take up the necessary quan- 
tity of evaporated gasoline for charging the air. 

The surface type has not been used to a large 
extent, but the sprayer is universally used, and 
of this kind there are many examples of construc- 
tion, each having some particular merit. 

Governing a Carbureter. — It is a curious thing 
that one carbureter will work admirably with one 
engine, and be entirely useless in another. This 
is due to several factors, both in the engine design 
and in the carbureter itself. The quality of mix- 
ture that an engine will take depends on its speed. 
The suction of the pistons depends on the speed 
of the engine. 

If, at ordinary speed the carbureter gives a 
proper mixture, the throats and passages through 
the pipes and manifold, as well as the valve which 
discharges the gasoline, may be in a prime condi- 
tion to do good work ; but when the pistons work 
at double speed the inrush of air may not carry 
with it the proper amount of fuel ; or, under those 
conditions, the air may receive too great an 
amount of gasoline, proportionally. 

The latter is usually the case, hence provision 
must be made for such a contingency, and we 



CARBURETERS 



87 



shall therefore take up the various features essen- 
tial in the construction of the carbureter, so as 
to show what steps have been taken to meet the 
problems arising from varying speeds, differ- 
ences in the character of the fuel, regulating the 




T*ig. 8L Carbureter . 

inflow and mixture of gasoline and air, and ad- 
justments. 

So many different types of carbureters have 
been devised, that it is difficult to select one which 
typifies all the best elements of construction. 



88 MOTOES FOR BOYS 

In Fig. 31 we have shown a well known con- 
struction, and which will illustrate the features 
of the sprayer type to good advantage. The body 
of the device, represented by A, has a flange by 
means of which it is secured to the pipe which 
carries the carbureted air to the engine. The 
lower end of this tubular body is contracted, as 
shown at B, so as to form what is called a ven- 
turi tube. 

Exteriorly this contracted tube is threaded, as 
shown at C, so as to receive thereon a threaded 
body D, the lower end of the body having an en- 
larged disk-head E, integral therewith, and an 
upwardly-projecting annular flange F is formed 
around this disk to receive and hold a cylinder G, 
which constitutes the float and fuel chamber. 

The upper end of this cylinder rests against 
a seat cast with the body A, and packing rings 
are placed at the ends of the cylinder to prevent 
the oil from leaking out. Within the tubular 
body D is a vertical tube H, integral with the disk 
head E, and oil is supplied to this tube through 
ducts I, which communicate with the chamber 
within the reservoir G. 

A drain cock is at the lower end of this tube, 
and an adjustable cap K screws on the tubular 
stem of the drain tube, around which air is ad- 
mitted, the air passing upwardly through vertical 



CARBURETERS 89 

ducts L, as shown, and thus mixes with air at the 
contracted part of the venturi tube. 

A ring-like float N is placed within the glass 
chamber, and this is adapted to engage with the 
inner end of a lever N', this lever being pivoted 
at 0, within a side extension P of the carbureter 
shell. The inner end of this lever has a link 
hinged thereto, the lower end of which serves as 
a needle valve to close the ejecting orifice of the 
tube L. 

The outer end of the lever N' engages a shoul- 
der on a vertically-disposed needle valve Q, which 
has its point in the inlet opening of the pipe R, 
through w T hich gasoline is supplied to the glass 
chamber. A spring T serves to keep the valve 
stem normally on its seat. 

Directly opposite this chambered extension P 
is another extension U, also cast with the shell, 
through which is a vertical stem V. This stem 
carries a downwardly-opening valve W, that seats 
against a plug, and a spring X below the valve, 
serves to keep it against its seat, unless there 
should be an extraordinarily heavy pull or suc- 
tion. 

This is the auxiliary air inlet, and the lower 
spring is actuated only when the engine is run- 
ning at moderate speeds, but when running at 
high speed and an additional quantity of air is 



90 MOTORS FOR BOYS 

required the upper spring Y is compressed, and 
thus a much greater quantity of air is allowed to 
pass in and mingle with the spray at the throttle 
valve Z. 

The throttle valve is mounted in the discharge 
opening, and is controlled by a lever on the out- 
side of the carbureter. 

The device operates as follows: Primary air 
enters the opening between the cup K and the 
disk-head E, passing up into the space around the 
oil tube H. As the spring T, around the needle 
valve Q, draws up the valve from its seat, oil is 
permitted to flow in through the duct R and fill 
the chamber, until the float engages with the inner 
end of the lever N, and raises it, thus uncovering 
the ejecting end of the tube H, and at the same 
time closing the inlet tube R. 

The suction from the engine then draws air 
through the primary duct, as stated, and also an 
additional quantity through the secondary source, 
by way of the valve W, this valve being so regu- 
lated as to supply the requisite quantity. 

The auxiliary air source serves the purpose that 
means should be provided to supply more than 
the ordinary amount of air, when running at high 
speeds. 

From the foregoing it will be observed that a 
carbureter must be so constructed that it will 



CARBURETERS 91 

perform a variety of work. These are: First, 
Automatic means for filling the float chamber 
when the gasoline goes below a certain level. 
Second, Cutting off the supply of gasoline. 
Third, Providing a primary supply of gasoline 
for spraying purposes. Fourth, Furnishing an 
auxiliary air supply. Fifth, Throttling means in 
the discharge opening. 

It is thus a most wonderful contrivance, and 
considering that all the elements necessary to 
make it work satisfactorily are provided with 
adjustable devices, it may be seen that to make it 
perform correctly requires a perfect understand- 
ing of its various features. 

Requirements in a Carbureter. — In view of 
the foregoing it might be well to know how to 
select a carbureter that is ideal in its operation. 

First. The adjustment of the auxiliary valve 
should be of such a character that at the slowest 
speed the valve should not be lifted from its 
seat. 

Second. It must be so arranged that it is not 
difficult to change the relative amount of air and 
gasoline. 

Third. The floating chamber should be so ar- 
ranged that the float will act on the lever which 
lifts the valve of the injecting pipe, even though 
the carbureter body should be tilted at an angle. 



92 MOTORS FOR BOYS 

This is particularly important when the carbure- 
ter is used in automobiles. 

Fourth. The valves should be in such position 
that they are readily accessible for cleaning or for 
examination. 

Fifth. The float should be so arranged that it 
is adjustable with reference to the lever that it 
contacts with. 

Sixth. A gauze strainer should be placed at 
the gasoline inlet, and it is also advisable to have 
a similar strainer above the mixing chamber, be- 
yond the throttle. 

Seventh. There should be no pockets at any 
point in the body to hold the gasoline which might 
condense. 

Eighth. The body of the carbureter should be 
so constructed that every part is easily accessible, 
and draining means provided so that every par- 
ticle of gasoline can be withdrawn. 

Ninth. Means for heating it, in case of cold 
weather. 

Size of the Carbureter. — The proper size of a 
carbureter for an engine has been the subject of 
considerable discussion and experimenting. If 
its passages are too large, difficulty will be experi- 
enced in starting the engine, because the pulling 
draft through the primary will not be sufficient to 
make a spray that will unite with the air. 



CARBURETERS 93 

A carbureter too large will only waste fuel, even 
after the engine lias been cranked up so it will 
start. 

If the carbureter is too small the engine will 
not develop its required output of power. While 
it might work satisfactorily at low speeds it would 
be entirely inefficient at high speeds. 

Rule for Size or Carbureter. — In all cases the 
valve opening and cylinder capacity in the engine 
should determine this. The size of the opening 
of the carbureter outlet should be the same as that 
of the engine valve, which is also the case where 
the carbureter supplies a multi-cylinder, as there 
is only one valve open at the same time. 

It was formerly the custom to use a carbureter 
for each cylinder but the practice has been aban- 
doned, because it is obvious that a single car- 
bureter will, owing to the continuous suction, sup- 
ply a mixture of more nearly uniform character 
than two or more, even though they should sup- 
ply the mixture to a common manifold. 

The Throttle. — Much of the economy in run- 
ning an engine depends on the manipulation of 
the throttle. As an example, with a certain motor 
and carbureter it will be found that for maximum 
speed the throttle should be open about one-eighth 
of the way. The proper way, in starting the en- 
gine, is to open the throttle fully half way, and 



94 MOTORS FOR BOYS 

to retard the spark. As soon as the engine begins 
to run properly, the spark is advanced and the 
throttle closed down to the required point. 

The engine speed may always be maintained by 
the throttle under a constant varying load, by 
adjusting the throttle valve. A rich mixture may 
be obtained by throttling the primary air sup- 
ply- 

The throttle may also be a most effective means 
of economizing fuel when the engine has a first 
class sparking device, as in that case the throttle 
can be closed down to provide a very small open- 
ing. 

Flooding. — One of the most prevalent troubles 
in carbureters is the liability to flood. This is 
usually caused by foreign matter getting under 
or in the float valve, so that it will not properly 
seat. Sometimes the mere moving of the float 
will dislodge the particle. 

Another cause of flooding is due, frequently, to 
an improperly-arranged float, which, when the 
engine is inclined, will prevent improper seating 
of the valve, and flooding follows. 

The greatest care should be exercised in seeing 
that the gasoline supply is free from all impuri- 
ties when it is poured into the tank. To strain 
it is the best precaution, and it pays to be particu- 
lar in this respect. It is surprising to see the 



CARBURETERS 



95 



smallest speck, either stop the flow entirely, or 
produce an overflow, either of which will cause 
a world of trouble. 

Water is another element which has no place 
in a carbureter. An indication of this is the ir- 
regular movement of the engine. The only 




T^ig. <32. Cai'&ureter 



remedy is to stop and drain the carbureter. A 
few drops may cause all the trouble. 

Types of Carbureters. — In Fig. 32 we show an- 
other type of carbureter, which is simple in con- 
struction, and has many desirable features. The 
cylindrical body of the carbureter, A, has a down- 



96 MOTORS FOR BOYS 

wardly-projecting globular extension B, at one 
side of which is a flange C to secure it to the 
pipe, and through this is the discharge opening D. 
This globular extension serves as the mixing 
chamber. 

Within the cylindrical shell is an upwardly-pro- 
jecting circularly-formed extension E, and the top 
or cap F of the cylindrical body A has a down- 
wardly-projecting cylindrical rim Gr which over- 
laps the lower circular extension E, and it is so 
constructed that a very thin annular slit H is 
thus formed between the two parts, through which 
fuel oil flows from the float chamber I into the 
space around the central tube J which passes 
down through the two circular extensions E, G. 

This central tube J is designed for the auxiliary 
air supply. It extends down to the globular base 
B, and has a valve K seated against its end. The 
stem L of the valve is vertically-movable within an 
adjustable stem M, and a helical spring N, ca- 
pable of having its tension adjusted by the stem 
M, bears upwardly against the valve so as to keep 
it normally against the lower end of the tube J. 

The auxiliary air, therefore, passes down cen- 
trally through the tube J, while the primary air 
supply passes through openings 0, surrounding 
the tube J, downwardly past the slitted opening 
H, and thence to the discharge port D. 



CARBURETERS 97 

Surrounding* the tubular projections E, Gr, and 
within the float chamber I, is the float P. This is 
designed to strike the bifurcated ends of a lever 
Q, which is hinged near its outer end, as at R, and 
has its short projecting end resting beneath the 
collar of a vertical needle valve S. 

This needle valve is vertically placed within a 
chambered extension T at the side of the shell A, 
and its lower end rests within the opening of the 
inlet U which supplies the gasoline to the cham- 
ber I. The upper end of the valve stem passes 
through a plug V, through which is a vent 
hole W. 

A spring X is used between the plug and the 
collar on the lower end of the needle valve, so 
that the valve is kept on its seat thereby, unless 
the gasoline in the chamber should fall so low as 
to cause the float to rest on the inner end of the 
lever Q, when the needle valve would be unseated 
thereby. 

All the parts of this device seem to be accessible, 
and it is presented as an example of construction 
that seems to meet pretty nearly all of the ideal 
requirements of a device for furnishing a perfect 
admixture. 

Surface Carbureter. — This type of carbureter 
also requires a float but does not have secondary 
air inlet mechanism. It has one striking advan- 



98 



MOTORS FOR BOYS 



tage over the sprayer system, in the particular 
that the suction of the engine is not depended 
npon to draw the gasoline from the float chamber. 
It is much more sensitive to adjustment in the 
float level and needle valve than the other type. 
The diagram, Fig. 33, shows a body A, some- 
what bowl-shaped, with a chambered extension, 




7^1 g. S3. -6icrface Cw'Swefv,? : 



B, at one side, at the lower side of which is the 
fuel inlet duct C. Directly above this duct the 
upper wall of the extension has a plug D, the lower 
end of which carries therein the upper end of a 
vertically-movable needle valve, E, the lower end 
of the valve resting within the duct C. 

A float F within the bowl-shaped body is se- 



CARBURETERS 99 

cured at one side to a lever G, which is hinged at 
a point near the needle valve E, and the short end 
of this lever connects with this needle valve in 
such a manner that as the float moves upwardly 
the valve is seated, and when the level of the fuel 
oil falls below a certain point the needle is lifted 
from its seat, and oil is permitted to flow into 
the float chamber. 

The cap H of the float chamber has cast there- 
with a U-shaped tube, the inlet end I being hori- 
zontally-disposed, while the discharge end J is 
vertical. Directly above the lowest part of the 
bend in this tube, the vertical dimension of the 
tube is contracted by a downwardly-projecting 
wall K, so as to form a narrow throat L. 

Below this contracted point, the U-shaped tube 
has integral therewith a downwardly-projecting 
stem M, the lower end of which passes through 
an opening in the float chamber, and is threaded, 
so as to receive a nut, by means of which the cap 
H may be firmly fixed to the float chamber. 

This stem M has a vertical duct N, which com- 
municates with the float chamber, and is provided 
with a drain plug 0. Alongside of this duct is a 
tube P which extends up into the U-shaped tube 
and is open at its lower end so that the level of 
the gasoline within the bent tube cannot extend 
above the end of this drain tube P. 



100 MOTORS FOR BOYS 

An adjustable valve stem Q passes through one 
side of the bent tube, the lower end being pointed 
and adapted to regulate the inflow of gasoline 
through the duct N, and into the U-shaped tube. 

A throttle valve R is placed in the discharge 
end of the U-shaped tube, which is susceptible of 
regulation by means of a lever S. The diagram 
shows the gasoline within the U-shaped tube, so 
that it is on a level with the gasoline in the float 
chamber. 

In operation a sufficient amount of gasoline is 
permitted to enter the float chamber so that a 
pool is formed in the bottom of the U-shaped tube. 
When suction takes place the air rushes through 
the tube, at I, down beneath the wall K, and in do- 
ing so it sweeps past the surface of the pool at 
that point, absorbing a greater or less amount of 
the vapor. 

In order to adjust the device so that a smaller 
amount of the liquid fuel will be exposed, the car- 
bureter is adjusted so it will close the needle 
valve before the level of the liquid is so high, and 
thereby a less surface of oil is formed within the 
U-shaped tube. 

It is obvious that this type of carbureter, owing 
to the absence of the secondary air-supply 
mechanism, can be readily regulated and all ad- 



CAEBURETERS 101 

justments made while running, while for auto- 
mobile uses the lever S, which controls the 
throttle, can be connected up with a dash-board 
control. 



CHAPTER VII 

IGNITION. LOW TENSION SYSTEM 

Electricity, that subtle force, which, manifests 
itself in so many ways, is nevertheless beyond the 
power of man to see. The only way in which we 
know of its presence is by the results produced by 
its movements, because it can make itself known 
to our senses only by some form of motion. 

The authorities regard light, heat and elec- 
tricity as merely different forms of motion. The 
most that can be done with such a force is to learn 
the laws governing it. 

Magnetism. — This is a form of electricity. In 
fact, it is one of the most universal manifesta- 
tions, for without it electricity would be useless. 
When the first permanent magnet was found at 
Magnesia, it was not considered electricity. The 
sciences had not arrived at that point where they 
were able to classify it as belonging to lightning 
and other manifestations of that kind which we 
now know to be electricity. 

The Armature. — But magnetism can no more 

be seen than electricity flowing through a wire. 

102 



IGNITION. LOW TENSION SYSTEM 103 

If a piece of metal lias magnetism it will attract 
a piece of iron or steel placed in close proximity, 
and thus we are permitted to see the action. 

The lightning in the upper atmosphere burns 
the gases in its path. This enables us to see, not 
the current, but its action, — the result produced 
by its power. 

The electric current has many peculiar man- 
ifestations, the causes of some of them being 
known and utilized. In the use of this medium for 
igniting the fuel gas, many of the phases of elec- 
trical phenomena are brought into play, and 
it is necessary, therefore, to know something of 
the fundamentals of the science to enable us to 
apply it. 

Characteristics of Electricity. — When a cur- 
rent passes along a wire, it does not describe a 
straight path, but it moves around the conductor 
in the farm of circles. The current is not con- 
fined wholly to the wire itself, but it extends out 
a certain distance from it at all points. 

Magnetic Field. — Every part of a wire which 
is carrying a current of electricity has, surround- 
ing it, a magnetic field, of the same character, and 
to all intents and purposes, of the same nature as 
the magnetic field at the ends of a magnet. 

Elasticity. — This current has also something 
akin to elasticity. That is, it surges to and fro, 



104 MOTORS FOR BOYS 

particularly when a current is interrupted in the 
circuit. At the instant of breaking a current in 
an electric light circuit there is a momentary flash 
which is much brighter than the normal light, 
which is due to the regular flow of the current. 

This is due to the surging movement, or the 
elastic tension, in the current. Advantage is 
taken of this characteristic, in making a spark. 
This spark is produced at the instant that the 
ends of the wires are separated. 

The Make and Break System. — No spark is 
caused by putting the two ends together, or by 
making the connection, but only by breaking it, 
hence it is termed the make and break method of 
ignition. 

When the connection is broken the current tries 
to leap across the gap, and in doing so develops 
such an intense heat that the spark follows. As a 
result of the high temperature it is necessary to 
use such a material where the gap is formed that 
it will not be burned. For this purpose platinum, 
and other metals are now employed. 

Voltage. — This plays an important part in ig- 
nition. Voltage is that quality which gives pres- 
sure or intensity to a current. It is the driving 
force, just as a head of water gives pressure to a 
stream of water. 

High and Low Voltage. — A high tension cur- 



IGNITION. LOW TENSION SYSTEM 105 

rent, — that is, one having a high voltage, will leap 
across a gap, whereas a low voltage must have an 
easy path. When the ends of a wire in a circuit 
are separated, air acts as a perfect insulator be- 
tween them, and the slightest separation will pre- 
vent a low current from jumping across. 

This is not the case with a high tension cur- 
rent, where it will leap across and produce the 
flash known as the jump spark. 

Low Tension System. — Two distinct types of 
ignition have grown out of the voltage referred 
to, in which the make and break system uses the 
low tension, because of its simplicity in the electri- 
cal equipment. 

Disadvantages of the Make and Break. — 
There is one serious drawback to the extended 
use of this system, and that is the necessity of 
using a moving part within the cylinder, to make 
and break the contact in the conductor, as it is 
obvious that this part of the mechanism must be 
placed within the compressed mixture in order to 
ignite it. 

Amperes. — A current is also measured by am- 
peres, — that is, the quantity flowing. A large con- 
ductor will take a greater quantity of current 
than a small one, just as in the case of water a 
large pipe will convey a greater amount of the 
liquid. 



106 MOTORS FOR BOYS 

Resistance. — All conductors offer resistance to 
the flow of a current, and this is measured in 
Ohms. The best conductor is silver and the next 
best is copper, this latter material being used 
universally, owing to its comparative cheapness. 

Iron is a relatively poor conductor. Resistance 
can be overcome to a certain extent, however, if 
a large conductor is used, but it is more economi- 
cal to use a small conductor which has small re- 
sistance, like copper, than a heavy conductor, as 
iron, even though pound for pound the latter may 
be cheaper. 

Direct Current. — There are two kinds of cur- 
rent, one which flows in one direction only, called 
the Direct. It is produced in a dynamo which has 
a pair of commutator brushes so arranged that 
as the armature turns and its wires move through 
the magnetic fields of a magnet, and have direc- 
tion of the current alternate, these brushes will 
change the alternations so the current will travel 
over the working conductors in one direction only. 

Primary and secondary batteries produce a 
direct current. These will be described in their 
appropriate places. 

Alternating Current. — This is a natural cur- 
rent. All dynamos originally make this kind of 
current, but the commutator and brushes in the 
direct current machine change the output method 



IGNITION. LOW TENSION SYSTEM 107 

only. The movement of this current is likened to 
a rapid to and fro motion, first flowing, for an 
instant, to one pole, and then back again, from 
which the term alternating is derived. 

While the sudden breaking in a circuit will 
produce a spark with either the direct or the 
alternating currents, the direct is usually em- 
ployed for the make and break system, since bat- 
teries are used as the electrical source. 

On the other hand the jump spark method em- 
ploys the alternating current, because the high 
tension can be most effectively produced through 
the use of induction coils, which will be explained 
in connection with the jump spark method of igni- 
tion. 

Generating Electricity. — There are two ways 
to produce a current for operating an ignition sys- 
tem, one by a primary battery, and the other by 
means of a magneto, a special type of dynamo, 
which will be fully explained in its proper place. 

Primary Battery. — As we are now concerned 
with the make and break system, the battery type 
of generation, and method of wiring up the same, 
should first be explained. 

Thus, in Fig. 34, a primary battery is shown, 
in which the zinc cell A has an upwardly-project- 
ing wing B at one side, to which the conductor is 
attached; and within, centrally, is a carbon bar 



108 



MOTORS FOE BOYS 



C. An electrolyte, which may be either acid or 
alkali, must be placed within the cell. 

Making a Dry Cell. — The zinc is the negative, 
and the carbon the positive electrode. The best 
material for the electrolyte is crushed coke, which 
is carbon, and dioxide of manganese is used 



Carbojz 



IP=§i-z^ 




for this purpose, and the interstices are filled 
with a solution of sal-ammoniac. 

The top of the cell is covered with asphaltum, 
so as to retain the moistened material and the 
liquid within the cell, and thus constituted, it is 
called a dry cell. 

Energy in a Cell. — A battery is made up of a 
number of these cells. Each cell has a certain 



IGNITION. LOW TENSION SYSTEM 109 

electric energy, usually from one and a half to one 
and three-quarter volts, and from twenty-five to 
forty amperes. 

The amperage of a cell depends on its size, or 
rather by the area of the electrodes ; but the volt- 
age is a constant one, and is not increased by the 
change, formation, or size of the electrodes. 

For this reason the cells are used in groups, 
forming, as stated, a battery, and to get efficient 
results, various methods of connecting them up 
are employed. 




JF^lO. 36. <6erie-6 Connection 

Wiring Methods. — As at least six cells are re- 
quired to operate a coil, the following diagrams 
will show that number to illustrate the different 
types of connections. 

Seeies Connection. — The six cells, Fig. 35, 
show the carbon electrodes A, of one cell, con- 
nected by means of a wire B with the zinc elec- 
trode wing C of the next cell, and so on, the cell 
at one end having a terminal wire D connected 
with the zinc, and the cell at the other end a wire 
E connected with the carbon electrode. 



110 MOTORS FOR BOYS 

The current, therefore, flows directly through 
the six cells, and the pressure between the 
terminal wires D, E, is equal to the combined 
pressure of the six cells, namely, 1% x 6> which is 
equal to 9 volts. The amperage, however, is that 
of one cell, which, in these diagrams, will be as- 
sumed to be 25. 

Parallel Connection. — Now examine Fig. 36. 
In this case the carbon electrodes A are all con- 
nected up in series, that is, one following the 
other in a direct line, by wires B, and the zinc 




2 r %g.$6. THuZtipZe . or Parallel Connection . 

electrodes C, are, in like manner, connected up in 
series with each other by wires D. The differ- 
ence in potential at these terminals B, D, is the 
same as that of a single cell, namely, one and a 
half volt. 

The amperage, on the other hand, is that of the 
six cells combined, or 150. This method of con- 
necting the cells is also called parallel, since the 
two wires forming the connections are parallel 
with each other, and remembering this it may be 
better to so term it. 



IGNITION. LOW TENSION SYSTEM 111 

Multiple Connections. — This is also desig- 
nated as series multiple since the two sets of cells 
each have the connections made like the series 
method, Fig. 35. The particular difference being, 
that the zinc terminals of the two sets of cells 
are connected up with one terminal wire A, and 
the carbon terminals of the two sets are joined to 
a terminal B. 

The result of this form of connection is to in- 
crease the voltage equal to that of one cell mul- 




JSattery Jfat 
Battery JfoJl 



^T^ff- 37, -tierJed - Tnulitple Connection. 

tipled by the number of cells in one set, and the 
amperage is determined by that of one cell mul- 
tiplied by the two sets. 

Each set of cells in this arrangement is called 
a battery, and we will designate them as No. 1, 
and No. 2. Each battery, therefore, being con- 
nected in series, has a voltage equal to 4% volts, 
and the amperage 50, since there are two batteries. 

Now the different arrangement of volts and 
amperes does not mean that the current strength 



112 MOTORS FOR BOYS 

is changed in the batteries or in the cells. If the 
pressure is increased the flow is lessened. If the 
current flow, or the quantity sent over the wires 
is increased, the voltage is comparatively less. 

Watts. — This brings in another element that 
should be understood. If the current is multi- 
plied by the amperes a factor is obtained, called 
Watts. Thus, as each cell has l 1 /^ volts and 25 
amperes, their product is SI 1 /** watts. 

To show that the same energy is present in each 
form of connection let us compare the watts de- 
rived from each: 

Series connection : 9 volts X 25 amperes, equal 
225 watts. 

Parallel connection : iy 2 volts X 150 amperes, 
equal 225 watts. 

Series Multiple connection: 4% volts X 50 
amperes, equal 225. 

From the foregoing, it will be seen that the 
changes in the wiring did not affect the output, 
but it enables the user of the current to effect such 
changes that he may, for instance, in case a bat- 
tery should be weak, or have but little voltage, 
so change connections as to temporarily increase 
it, although in doing so it is at the expense of 
the amperage, which is correspondingly de- 
creased. 

It would be well to study the foregoing com- 



IGNITION. LOW TENSION SYSTEM 113 

parative analysis of the three forms of connec- 
tions, so far as the energy is concerned, because 
there is an impression that increasing the volt- 
age, is adding to the power of a current. It does 
nothing but increase the pressure. There is not 
one particle of increase in the energy by so doing. 
Testing a Cell. — The cells should be frequently 
tested, to show what loss there is in the amperage. 
This is done by putting an ammeter in the circuit. 




Cell 



jTty.SS. Ci7cui£ T T e6tirtg . 

If a meter of this kind is not handy, a good plan 
is to take off one of the wire connections, and snap 
the wire on the terminal, and the character of the 
spark will show what energy there is in the cell. 
Testing With Instruments. — The method of 
testing with voltmeter and ammeter, is shown in 
Fig. 38. The voltmeter is placed in a short cir- 
cuit between the two terminal wires, whereas the 
ammeter is placed in circuit with one of the wires. 
The reason for this is that the voltmeter registers 



114 



MOTORS FOR BOYS 



the pressure, the power, or the difference of po- 
tential between the two sides of the cell, and the 
ammeter shows the quantity of current flowing 
over the wire. 

In practice batteries are not used continuously 
for igniting. They are temporarily employed, 




2^10.89. MaTcQ <znd . Hi r ea7G . uitk2}citte?y . 



principally for starting, because their continued 
use would quickly deplete them. 

Simple Batteey Make and Beeak System. — In 
order to show this method in its simplest form, 
examine Fig. 39, which diagrams the various parts 
belonging to the system. 

We have illustrated it with two cylinders, por- 
tions of the heads being shown by the outlines A, 
A. B, B represent terminals which project into 
the cylinders, and are insulated from the engine 



IGNITION. LOW TENSION SYSTEM 115 

heads. Through the sides of the engine heads are 
rock shafts C, the ends within the cylinder having 
fingers D which are adapted to engage with the 
inner ends of terminals B, B. 

On the ends of the rock shafts outside of the 
cylinders, they are provided with levers E, E, one 
end of each being attached to a spring F, so that 
the tension of the spring will normally keep the 
upper end of the finger D in contact with the 
terminal B. The cut shows one finger engaging 
with B, and the other not in contact. 

The other end of the lever E rests beneath a col- 
lar or shoulder G on a vertical rod H. The lower 
end of this rod engages with a cam I on a shaft J, 
and when the cam rotates the rod drops off the 
elevated part of the cam, and in doing so the 
shoulder Gr strikes the end of the lever E and 
causes the finger to rapidly break away from the 
terminal B, where the spark is produced. 

To Advance the Spaek. — For the purpose of 
advancing or retarding the spark, this rod has, 
near its lower end, a horizontally-movable bar K, 
which may be moved to and fro a limited distance 
by a lever L, this lever being the substitute in 
this sketch of the lever on the steering wheel of 
an automobile. 

The spark is advanced or retarded by causing 
the lower end of the rod H to be moved to the left 



116 MOTORS FOR BOYS 

or to the right, so that it will drop off of the raised 
portion of the cam earlier or later. 

The wiring up is a very simple matter. The 
battery M has one end connected up with one 
terminal of a switch N, while the other terminal 
of the switch has a wire connection with the 
terminal plugs B, B, in the cylinder heads. 

The other end of the battery is connected with 
the metal of the engine, which may be indicated 
by the dotted line which runs to the rock shaft 
C, and thus forms a complete circuit. 

The operation is as follows : When the key P 
of the switch is moved over so that it contacts 
with the terminal N, the battery is thrown into 
the circuit, and the current then passes to the 
plug B of the first cylinder, as the finger D in 
that cylinder is in contact with that terminal, and 
it passes along the finger D, and rock-shaft C, to 
the metal of the engine, and passes thence to the 
battery, this course being indicated by the dotted 
line 0. 

At the same time, while cylinder No. 2 is also 
connected up with the battery, the shoulder of the 
rod H has drawn the finger D from its contact 
with the plug B, hence the current cannot pass in 
that direction. 

As the cam I, of cylinder No. 1, turns in 
the direction of the arrow, the rod drops down 



IGNITION. LOW TENSION SYSTEM 117 

and suddenly makes a break in the terminal of 
this cylinder, causing the ignition, to be followed 
by a like action in No. 2. 

The Magneto in the Circuit. — To insure the 
life of the battery, so that it may be in service 
only during that period at the starting, when the 



^ 




T^igAO. Make and Break . tvltk M agneto . 

magneto is not active, the latter is so placed in the 
circuit, that, at the starting, when, for instance, 
the automobile is being cranked, it is cut out by 
the switch on the dash board. 

In Fig. 40, a simple two-pole switch is used. 
With the magneto it is necessary to have a three- 
point switch, E, and a plain coil S is placed be- 
tween the switch and battery. 

One side of the Magneto T is connected by wire 
U with one of the points of the switch R, and the 



118 MOTORS FOR BOYS 

other side of the magneto is connected with the 
metal of the engine, which is indicated by the 
dotted line V. 

In all other respects the mechanism is the same. 
The starting operation has been explained with 
reference to the preceding figure, and when the 
engine has picked up, and is properly started, the 
switch bar is thrown over so it contacts with the 
point connected np with the wire U leading to the 
magneto. 

This, of course, cuts out the battery, and the 
engine is now running on the magneto alone. 
The object of the coil S is to oppose a rapid change 
of the current at the moment of the interruption. 
The coil induces a counter current the moment 
the break is made, and as the current continues 
to flow for a very short period after the break a 
spark of greater intensity is produced than if the 
circuit should be permitted to go from the battery 
to the sparker directly, as in the previous illustra- 
tion. 

The best spark is produced by quickly making 
the break between the points B, D, so that par- 
ticular attention has been given to mechanism 
which will do this effectively. 

Magneto Spark Plug. — One of the devices to 
obviate the difficulty of providing moving mech- 
anism outside of the engine cylinder, is shown in 



IGNITION. LOW TENSION SYSTEM 119 

Fig. 41. In this the coil A is connected with a 
terminal B at the head of the device and the 
other is connected to the ping C which screws into 
the cylinder head. 




JT'ig.^f. Magneto d p ark Tlug . 

"Within the core is a pivotally-mounted lever D, 
the upper end E of which is attracted by the 
tubular metallic core F, and the lower end having 
a contact point Gr, which is adapted to engage 
with a stationary point H. 



120 MOTORS FOE BOYS 

The pivot I, on which the lever D is mounted, 
provides a means whereby the lever swings, and 
a spring J is so arranged that when the lower end 
of the lever is disengaged from the contact, the 
spring will return it to its normal position, 

In its operation when a contact is formed by 
the timing device of the magneto^ so as to give a 
spark, the circuit passes to the terminal B, coil 
A, and plug C, thus forming a complete circuit. 
This energizes the core A, pulling the upper end 
of the lever, and at the same time causes the lower 
end to disengage the two contacts G, H, which 
breaks the circuit and produces a spark. 

The breaking of the circuit deenergizes the core, 
and the spring again draws the lever back to its 
normal position, ready for the next completion of 
the circuit by the timing device. 

Such an arrangement is as simple as the spark 
plug usually employed in the use of the high ten- 
sion system, although it is more expensive than 
the plug. 



CHAPTER VIII 

IGNITION. HIGH TENSION 

This system is used to the largest extent, so 
that we ought to have a full explanation of the 
devices which are required to do the work. While 
magnetos are used with the low tension system, 
for the reasons stated, they are especially neces- 
sary with the Jump Spark method. 

Magnetos. — The most important element in this 
system is the magneto, so we shall try and make 
the subject as explicit as possible. As stated, a 
magneto is a special type of dynamo which will 
now be explained. For this purpose it will be 
necessary to show the elementary operation of an 
alternating current dynamo. 

Alternating Cubeent. — In Fig. 42 A is a bar 
of soft iron, around which is a coil of wire B, 
the wire being insulated, so that it will not touch 
the bar. There is no magnetism in this bar, and 
this simple form of structure is shown, merely to 
represent what is called the field of a dynamo. 

The object of the coil of wire is to make a mag- 
net of the bar, for the moment a current is sent 

121 



122 



MOTORS FOR BOYS 



over the wire, a magnet is formed, and the mag- 
netism leaves the bar the moment the current 
ceases to flow. If this bar should be of hard steel 
it would retain the magnetism. 

Now, the primary difference between the mag- 
neto and the dynamo, is that this field bar is a 




T^ig.m .iniMSfratt?^ Mternatviy Current : 




T^ig. 43. </Hte7naltno Current . Second podzlion. 



permanent magnet in the magneto, whereas the 
field is only a temporary magnet in the dynamo. 
This should always be kept in mind. 

The end of a magnet, whether it is a tem- 
porary one, or permanent, has a magnetic field of 
force at the ends as well as at all parts of it, ex- 
terior to the surface of the bar. Such a field is 



IGNITION. HIGH TENSION 123 

indicated, and in the dynamo, no such field exists 
unless a current is passing over the wire B, which 
is called the field winding. 

The U-shaped piece of metal C represents the 
armature. It is shown hinged to the top of two 
posts, for clearness in understanding, and is 
adapted to turn to the right, and in turning the 
loop passes the end of the field bar B, and passes 
through the magnetic field which is indicated by 
the dotted lines D. 

Now, if the loop is simply permitted to remain 




T^ig. 4f. c/Iltemaiing Current Thi7dtto6iiio7t . 

in the position shown in Fig. 42, a current would 
flow through the loop, this transference of the cur- 
rent being called induction, and this characteris- 
tic of the flow of electricity will be explained and 
its utility explained. 

Cutting Lines of Foece. — The loop will now be 
turned to the right so that it passes the magnetic 
field and goes beyond it in its revolution. This 
motion of passing the armature through the mag- 
netic field is called cutting the lines of force. 



124 MOTORS FOR BOYS 

While the loop was lying within the magnetic field, 
and also when it was moving through the field, the 
current set up in the loop flowed in the direction 
of the darts F, or to the right, through the pivots 
D. 

In Fig. 43 the loop is shown as having made a 
quarter turn, and it is now vertical, or at right 
angles to its former position. The loop in thus 
passing away loses its force, until it reaches the 
position shown in Fig. 44, when there is a surging 




F^iff. 40. Jlltemati?tg Cu7re7tt . 7 r bu7tk position . 

back of the current to the opposite direction, as 
indicated by the arrows. 

When the loop reaches the lowest position, 
shown in Fig. 45, it again begins to get the influ- 
ence of the magnetic field, and a reversal back to 
its former direction takes place, this surging 
movement back and forth being due to the re- 
versal of the polarity in the coil brought about by 
the position in which it is placed relative to the 
magnetic field. 

It is now an easy matter to connect the ends of 



IGNITION. HIGH TENSION 



125 



the loop with wire conductors. This is shown in 
Fig. 46, where a small metal wheel G is placed on 
each end of the spindle, and in having a strip of 
metal bearing H on the wheel. These are not 
commutator brushes, but are merely wiping 
brushes to take the current from the turning 
parts. , Wires I connect with these wiping bars, 
and through them the current is transmitted to 
perform the work. 

Plurality of Loops. — The dynamo may have a 




2 7 ~z£.^6'. Aiaki?ta ~the Circuit . 

plurality of loops, which are called coils, and 
there may be a single magnet or any number of 
magnets. Instead of driving these coils past the 
face of the magnet, or magnets, the latter may 
be driven past the coils. In fact with most of 
the alternating current machines the fields are 
the rotating parts and the armatures, or the coils, 
are fixed. 

The voltage is increased if the coils have a 
large number of turns on the armature, and also 
if the armature, or the turning part, is speeded 



126 



MOTORS FOR BOYS 



up. Voltage will also be higher if larger or more 
powerful magnets are used in the magnetos. 

The Electro-Magnet. — The permanent mag- 
net, such as is used in the magneto, is distin- 
guished by the fact that it contains a permanent 
charge of magnetism, but this is not an electro- 
magnet. This is a magnet made of soft iron, so 




Tly 47 The 7? i/?zamo . I^ip. 48. The Magneto . 



it will be readily demagnetized. While not 
shown in the diagrams, an iron core may be 
placed within the loop or coil, and this is done in 
all dynamos, because the iron core acts as a car- 
rier of the magnetism, concentrating it at the cen- 
ter, because it is a much better conductor than air. 
The Dynamo Form. — Consult the diagram, Fig. 
47. The iron heads A represent the bar in the 



IGNITION. HIGH TENSION 127 

previous diagrams, and B the wire around the 
bar. C is the armature, which in this case repre- 
sents a number of loops, or coils, and D is the 
commutator, which is used in the direct current 
machine to correct the alternations referred to in 
the previous diagrams, so as to send the current 
in one direction only, the commutator brushes E 
being used to cany off the current for use. 

The Magneto Form. — The metal loop F, in Fig. 
48, being a permanent magnet, the armature, G, 
formed of a plurality of loops, has no field wires 
to connect with it, as in the case of the dynamo. 

Advantage of the Magneto. — The magneto has 
a pronounced advantage over the dynamo, as a 
source of power for ignition purposes, in the par- 
ticular that the strength of the magnetic field is 
constant. In a dynamo this varies with the out- 
put, because when used on an automobile where 
the speed is irregular, the voltage will vary. The 
voltage of the magneto is a constant one, and is 
thus better adapted to meet the needs of ignition. 

Induction Coil. — The induction coil is a device 
which is designed to produce a very high voltage 
from a low tension, so that a current from it will 
leap across a gap and make a hot spark. 

We stated in a previous section that a current 
leaps across from one conductor to another, so 
that electricity can be transferred from a wire 



128 MOTORS FOR BOYS 

to another not touching it, by means of induction. 
Look at Fig. 49, which represents two wires side 
by side. The current is flowing over one wire A, 
and by bringing wire B close to A, but not touch- 
ing it, a current will be induced to leap across the 
gap and the wire B will be charged. If the ends 
of the wire B are brought together, so as to form a 
circuit, and a current detector is placed in the 
circuit it will be found that a current is actually 
flowing through it, but it is now moving in a direc- 
tion opposite to the current flowing through A. 



Jl 



Changing the Current. — But we have still an- 
other thing to learn. If the two wires are not of 
the same thickness it would not prevent the cur- 
rent from leaping across, but another astonishing 
thing would result. 

First, we shall use a wire B double the thick- 
ness of wire A. If now, we had an instrument to 
test the voltage and the amperage, it would be 
found that the voltage in B is less than that in A, 
and also that the amperage is greater. 

Second, if the conditions are reversed, and the 
wire A is thicker than B, the latter will have an 



IGNITION. HIGH TENSION 129 

increase of voltage, but a lower ampere flow than 
in A. 

Now this latter condition is just what is neces- 
sary to give a high tension. Voltage is neces- 
sary to make a current leap across a gap. By 
this simple illustration we have made an induc- 
tion coil which may be used for making a high 
tension jump spark. 

Construction of a Coil. — Two wires side by 




JS 7 

7^1 ff. <-)Q. TnductiOTZ Coil . 

side do not have the appearance of a coil, and 
even though such an arrangement might make a 
high tension current, it would be difficult to ap- 
ply. To put the device in such a shape that it 
can be utilized, a spool is made, as shown in 
Fig. 50. 

This spool A has a number of layers of thick, 
insulated wire B first wound around it, the layers 
being well insulated from each other, and the op- 



130 MOTORS FOE BOYS 

posite ends brought out at one end or at the oppo- 
site ends, as shown at C, D. On this is a layer of 
finer wire, also insulated, this wire E having its 
terminals also brought out at the ends of the spool, 
and after the whole is thus wound, the outside of 
the coil is covered with a moisture proof material. 
The Primary Coil. — The winding of thick wire 
is called the primary coil. The current from the 




jF^tg. $1+ Tfy pical ThdiLctzan Coil . 

battery or the electric generator is led to this 
inner coil. 

The Secondary Coil. — The fine wire wrap- 
ping represents the secondary coil, which is raised 
to a high voltage, and this actuates the sparking 
mechanism. 

In the art it Js : customary to illustrate the vari- 
ous contrivances by certain conventional forms. 
Fig. 51 shows the manner of designating an in- 
duction coil in a diagram, in which the heavy zig- 
zag line indicates the primary, and the lighter 
zig-zag lines the secondary coil. 



IGNITION. HIGH TENSION 131 

Contact Maker. — A simple little device used in 
the primary circuit of an induction coil, is known 
as a contact maker. This, as shown in Fig. 52, 
is merely a case A, through which is a shaft B 
that carries within the shell a cam C. A spring 
ringer D has its free end normally bearing against 
the cam, and when the nose on the cam moves out 
the spring finger, the latter is moved outwardly 



T 7 !^. cT>£. ContactfoaJzeK 

so it contacts with a plug E in the side wall of the 
case, although it is insulated therefrom. This 
contact establishes a current through the plug, 
spring finger and case. 

The diagram, Fig. 53, illustrates the principles 
of construction and arrangement of a high ten- 
sion jump spark ignition, in which the electrical 
source is a battery actuating an induction coil. 

High Tension With Battery and Coil. — The 
battery A has one side connected up by wire B 
with one terminal of the primary C in the induc- 
tion coil, and the other side of the battery has a 



132 



MOTORS FOR BOYS 



wire D leading to the contact maker. A switch E 
is placed in the line of this wire. 

The other terminal of the primary has a wire 
F leading to the insulated contact plug Gr of the 
contact maker. This completes the generating 





Hi 




^£ 



T^tff. 33. Ty pical Circuiting * Jump tipari I gnition . 

circuit. The cam H is on a shaft I, which travels 
one half the speed of the engine shaft. 

One side of the secondary coil J has a wire K 
leading to the spark plug, while the other terminal 
of the secondary has a wire L which is grounded 
on the engine M. 

When the nose of the cam pushes over the 



IGNITION. HIGH TENSION 133 

spring finger and closes the cam, the circuit 
through the finger flows through the primary 
coil and excites the secondary. When the cam 
again immediately breaks the circuit a high ten- 
sion current is momentarily induced in the sec- 
ondary, so that the current leaps the gap in the 
spark plug and makes the spark. 

Metallic Coke for Induction Coil. — In the 
previous description of the induction coil it was 
stated that the spool might be made of wood. 




J^ig. 64. Metacttc Core, T?tduction Coll . 

These coils are also provided with metal cores, 
which can be used to make what is called a vibra- 
tory coil. 

The Condenser. — A necessary addition to the 
circuiting provided by an induction coil, is a con- 
denser. This is used in the primary circuit to ab- 
sorb the self -induced current of the primary and 
thus cause it to oppose the rapid fall of the pri- 
mary current. 

The condenser is constructed of a number of 
tinfoil sheets, of suitable size, each sheet having 



134 MOTORS FOE BOYS 

a wing at one end, and these sheets are laid on 
top of each other, with the wings of the alternate 
sheets at opposite ends. Very thin sheets of 
waxed paper are placed between the tin foil 
sheets so that they are thus insulated from each 
other. 

The wings at the ends are used to make con- 
nections for the conducting wires. The device 
is not designed to conduct electricity, but to act 
as a sort of absorbent, if it might so be termed. 
The large surface affords a means where more or 



T^Q. <$& ConcU>n4p,r . 

less of the current moves from the conductor at 
one end to the conductor at the other end, and 
as it is designed to absorb a portion of the current 
in the line it is merely bridged across from one 
side of the circuit to the other. 

The diagram, Fig. 55, represents the conven- 
tional form of illustrating it in sketching electri- 
cal devices. 

Operation of a Vibrator Coil. — The illustra- 
tion, Fig. 56, shows the manner in which a vi- 
brator coil is constructed and operated. The coil 
comprises a metal core A, the primary winding 



IGNITION. HIGH TENSION 



135 



B being connected at one terminal, by a wire C, 
with a post D, and the other terminal by a wire 
E with one side of a battery F. A switch G is 
in the line of this conductor. 

The post D holds the end of a vibrating spring 




jftg. 66. Vibrator Coil and Connection^. 

H, which has a hammer H' on its free end, which 
is adapted to contact with the end of the metal 
core A, but is normally held out of contact, so 
that it rests against the end of an adjusting screw 
I which passes through a post J. 

The post J is connected up with the battery by 
a wire K, and a wire L also runs from the wire K 
to the conductor C, through a condenser M. 



136 MOTORS FOR BOYS 

The secondary coil N, has the outlet wires 0, 
P, which run to the spark plug Q on the engine. 

The operation is as follows : When the switch 
G closes the circuit, the battery thus thrown 
in the primary coil magnetizes the core A, and the 
hammer H' is attracted to the end of the core, 
thus breaking the circuit at the contact screw I. 
The result is that the core is immediately de- 
magnetized, and the spring H draws the hammer 
back to be again attracted by the core which is 
again magnetized, so that the hammer on the vi- 
brator arm H goes back and forth with great 
rapidity. 

From the foregoing explanations it will be un- 
derstood how the primary induces a high tension 
current in the secondary, and in order that the 
spark may occur at the right time, a timer for 
closing and opening the primary circuit must be 
provided. By this means an induced high ten- 
sion current is caused to flow at the time the spark 
is needed in the cycle of the engine operation. 

The Distributer. — The distributer is a timing 
device which controls both the primary and the 
secondary currents, and it also has reference to 
the revolving switch on the shaft of a magneto 
whereby the current is distributed to the various 
cylinders in regular order. 

Fig. 57 shows a form of distributer which 



IGNITION. HIGH TENSION 



137 



will illustrate the construction. A is the shaft 
which is driven at one half the engine speed. It 
is usually run by suitable gearing direct from the 
shaft of the magneto. 
Its outer end rests in a bearing plate B, of in- 




sulating material, which plate serves as the disk 
to hold the contact plates, 1, 2, 3, 4, to correspond 
with the four cylinders to which the current is 
to be distributed. 

Wires 5, 6, 7, and 8, run to the respective spark 
plugs C from these contact plates. The project- 
ing end of the shaft A carries thereon a contact 
finger D, which is designed to contact with the 
respective plates, and an insulating ring E is inter- 



138 



MOTOES FOR BOYS 



posed between the shaft and finger so as to pre- 
vent short circuiting of the high tension current. 
On the side of the finger is a hub F, integral 
therewith, and a wiper attached to a post bears 




u www u 



-=- y 

J^zg. <58. Circuiting with DiAfributiei - 

against the hub so as to form continuous contact. 
A wire leads from the post to one terminal of the 
secondary coil. 

Circuiting With Distributer.— The diagram 
Fig. 58 shows the complete connections of a sys- 



IGNITION. HIGH TENSION 139 

tern which comprises a magneto, induction coil, 
condenser, and a distributer. The magneto A has 
on its armature shaft B two revolving disks C, D, 
one of which must be insulated from the shaft, 
and one end of the coil E of the armature is con- 
nected with one of these disks, and the other end 
of the coil is attached to the other disk. 

Alongside of these disks is another disk F which 
has projecting points G to engage with and make 
temporary contact with a spring finger which ac- 
tuates the interrupter I, this being a contact 
breaker w T hich breaks the primary current at the 
time a spark is required. 

One terminal of this interrupter is connected by 
a wire J with one end of the primary winding K, 
of the induction coil, and the other end of the pri- 
mary has a wire L which runs to the disk C. 

The other terminal of the interrupter has a wire 
M leading to a condenser N, and from the other 
side of the condenser is a wire leading to the 
wire J before described. The wiper of the other 
disk D has a wire connection with the wire M. 

The distributer shaft P is so mounted that it 
may receive its motion from the shaft of the mag- 
neto, and for this purpose the latter shaft has a 
gear Q one half the diameter of the gear R on 
the distributer shaft. 

The distributer S has been described with suf- 



140 MOTORS FOR BOYS 

ficient clearness in a preceding diagram, to show 
how the wires T lead therefrom and connect up 
with the spark plugs U. One terminal of the 
secondary coil V is connected by a wire W with 
the wiper X which contacts with the hub of the 
distributer finger X', and the other terminal of 
the primary is grounded at Y, which represents 
the metal of the engine. 



CHAPTER IX 

MECHANICAL DEVICES UTILIZED IN POWER 

One of the most important things in enginery 
is the capacity to determine the power developed. 
Although the method of ascertaining this appears 
to be somewhat complicated, it is really simple, 
and will be comprehended the more readily if it 
is constantly borne in mind that a certain weight 
mnst be lifted a definite distance within a par- 
ticular time. 

The Unit of Time. — The unit of time is either 
the second, or the minute, usually the latter, be- 
cause it would be exceedingly difficult to make the 
calculations, or rather to note the periods as short 
as a second, and a very simple piece of mechanism 
to ascertain this, is to mount a horizontal shaft 
A, Fig. 59, in bearings B, B, and affix a crank C 
at one end. 

It will be assumed that the shaft is in anti- 
friction bearings so that for the present we shall 
not take into account any loss by way of friction. 

A cord, with one end attached to the shaft and 
the other fixed to a weight D, the later weighing, 

141 



142 



MOTORS FOR BOYS 



say 550 pounds, is adapted to be wound on the 
shaft as it is turned by the crank. 

Knowing the length of the cord and the time 
required to wind it up, it will be an easy matter to 
figure out the power exerted to lift the weight, 
which means, the power developed in doing it. 




uco 



JFlff. 69. IlluZfratiHci the Z/mfrof Time 

Suppose the cord is 100 feet long, and it re- 
quires one and a half minutes to raise the weight 
the full limit of the cord. It is thus raising 550 
pounds 100 feet in 45 seconds. 

One horse power means that we must raise 
550 pounds one foot in one second of time, hence 
we have developed only l/45th of one horse 
power. 

Instead of using the crank, this shaft may be 
attached to the engine shaft so it will turn slowly. 
Then add sufficient weight so that the engine will 
just lift it, and wind the cord on the shaft. 



MECHANICAL DEVICES IN POWER 143 

You can then note the time, for, say, one minute, 
and when the weight is lifted, make the following 
calculation: Weight lifted one hundred feet in 
one minute of time w r as 825 pounds. Multiply 100 
hy 825, which equals 82,500. This represents 
foot pounds. 

As there are 33,000 foot pounds in a horse 




JF'ig.CO. The I>ronei / Jd?>aXe. 

power, 82,500 divided by this figure will show that 
2y 2 horse power were developed. 

The Proney Brake. — Such a device is difficult 
to handle, but it is illustrated merely to show the 
simplicity of the calculation. As a substitute for 
this mechanism, a device, called the Proney brake 
has been devised, which can be used without re- 
winding of a cord. This is accomplished- by 
frictional means to indicate the power, and by the 
use of weights to determine the lift. 

The following is a brief description of its con- 
struction : The engine shaft A, Fig. 60, which is 
giving out its power, and which we want to test, 



144 MOTORS FOR BOYS 

has thereon a pulley B, which turns in the direc- 
tion of the arrow; Resting on the upper side of 
the pulley is a block C, which is attached to a 
horizontal lever D by means- of bolts E, these 
bolts passing through the block C and lever D, 
and having their lower ends attached to the ter- 
minals of a short sprocket chain F. 

Block segments G are placed between the chain 
and pulley B, and when the bolts E are tightened 
the pulley is held by frictional contact between 
the block C and the segments G. 

The free end of the lever has a limited vertical 
movement between the stops H, and a swinging 
receptable I, on this end of the lever, is designed 
to receive weights J. 

The first thing to do is to get the dimensions of 
the pulley, its speed, and length of the lever. By 
measurement, the diameter of the pulley is six 
inches. To get the circumference multiply this by 
3.1416. The distance around, therefore, is a lit- 
tle over 18.84 inches. The speed of the pulley 
being 225 times per minute, this figure, multiplied 
by 18.84, gives the perimeter of the pulley 4239 
inches. 

As we must have the figures in feet, dividing 
4239 by 12, we have 353.25 feet. 

The length of the lever from the center of the 
pulley to the suspension point of the receptacle, 



MECHANICAL DEVICES IN POWEK 145 

is 4 feet, and this divided by the radius of the 
pulley (which is 6 inches), gives the leverage. 
One half of six inches, is three inches, or % of 
one foot, and 4 divided by this number, is Y 4", 
or 1% feet, which is the leverage. 

Now, let us suppose the weight J is 1200 pounds. 
This must be multiplied by the leverage, 1% feet, 
which equals 1800, and this must be multiplied by 
the feet of travel in the pulley, namely, 353.25, 
which is equal to 635,850. This represents foot 
pounds. 

Now, following out the rule, as there are 33,000 
foot pounds in a horse power, the foregoing figure, 
635,850, divided by 33,000, equals 19 horse power 
within a fraction. 

Eeversing Mechanism. — A thorough knowl- 
edge of the principles underlying the various me- 
chanical devices, and their construction, is a part 
of the education belonging to motors. One of the 
important structures, although it is very simple, 
when understood, requires some study to fully 
master. 

This- has reference to reversing mechanism, 
which is, in substance a controllable valve motion, 
whereby the direction of the valve is regulated at 
will. 

All motions of this character throw the valve 
to a neutral point which is intermediate the two 



146 



MOTOES FOR BOYS 



extremes, and the approach to the neutral means 
a gradual decrease in the travel of the valve 
until the reciprocating motion ceases entirely at 
the neutral position. 




j/T'ig. 61. JJouMe Accent? zc7leife7-6ing(xea? \ 




T^ig. 6£. Reversing Gear , + A/eufia2 . 

Double Eccentric Reversing Gear. — A well 
known form of gear is shown in Fig. 61, in which 
the engine shaft A has two eccentrics B, C, the 
upper eccentric B being connected with the upper 
end of a slotted segment J> by means of a stem 
E, and the other eccentric C is connected with the 
lower end of the segment by the stem F. The ec- 



MECHANICAL DEVICES IN POWER 147 

Gentries B, C, are mounted on the shaft so they 
project in opposite directions. 

The slotted segment carries therewith the pin 
G of a valve rod H, and the upper end of the 
segment has an eye I, to which eye is a rod J 
operated by a lever. 




J^iff. 6<3. TlcicrMng Gear . Rever6ed . 




J^ig. 64. &i?igle Eccentric 7tei/er6iw . Geai 



By this arrangement the link may be raised or 
lowered, and as the valve rod pin has no vertical 
movement, either the connecting link E or F may 
be brought into direct line with the valve rod H. 

Fig. 61 shows the first position, in which 
the valve rod H is in direct line with the up- 



148 MOTORS FOR BOYS 

per connecting rod E, actuated by the cam B. 
Fig. 62 shows the neutral position. Here 
the pin G serves as a fulcrum for the rocking 
movement of the segment ; whereas in Fig. 63 the 
valve rod H is in line with the lower connecting 
rod F, so that the valve is pushed to and fro by 
the eccentric C. 




J^iff- 66 % JBalancect Slide Ifctlve . 

It is more desirable, in many cases, to use a 
single eccentric on the engine shaft, which can be 
done by pivoting the segment L, Fig. 64, to a 
stationary support M, and connecting one end of 
the segment by a link N with the single eccen- 
tric 0. 

In this construction the valve rod P is shifted 
vertically by a rod Q, operated from the reversing 
lever, thus providing a changeable motion through 
one eccentric. 

Balanced Slide Valves. — In the chapter per- 



MECHANICAL DEVICES IN POWER 149 

taming to the steam engine, a simple form of 
slide valve was shown, and it was stated therein 
that the pressure of the steam bearing on the 
valve would quickly grind it down. To prevent 
this various types of balanced valves have been 
made, a sample of which is shown in Fig. 64. 

The valve chest A has in its bottom two ports 
C, D, leading to the opposite ends of the cylinder, 
and within is the sliding valve E, which moves 




J^ig. 66. l/cdve C?te6t Double 7>o?t£7x/tau& r 

beneath an adjustable plate F connected with the 
top or cover Gr of the valve chest. 

This is also modified, as shown in Fig. 66, in 
which case the slide valve H bears against the 
cover I at two points, so that as there is steam on 
the upper surface to a slightly greater area than 
on the lower side, there is sufficient downward 
pressure to hold it firmly on its seat, and at the 
same time not cause any undue grinding. This 
valve also has double exhaust ports J, J. 



150 



MOTORS FOR BOYS 



Balanced Throttle Valve. — Fig. 67 will give a 
fair idea of the construction of throttle valves, 
the illustration showing its connection with a sim- 
ple type of governor. 




jT'w. 67 balanced Throttla-Volm . 

Engine Governors. — Probably the oldest and 
best known governor for regulating the inlet of 
steam to an engine, is what is known as the Watt 
design. This is shown in Fig. 68. 

The pedestal A which supports the mechanism, 
has an upwardly-projecting stem B, to the upper 
end of which is a collar C, to which the oppositely- 



MECHANICAL DEVICES IN POWER 151 

projecting pendent arms D are hinged. These 
arms carry balls E at their free ends. 

The lower part of the stem has thereon a slid- 
ing collar F, and links G-, with their lower ends 




M 



'-& 



Z^ig. S.d &&zM Governor . 



hinged to the collar, have their upper ends at- 
tached to the swinging arms D. The collar has 
an annular groove at its lower end, to receive 
therein the forked end of one limb of a bell-crank 
lever H, the other limb of this lever being con- 
nected up with the engine throttle, by means of a 
link L. ' 



152 



MOTORS FOR BOYS 



Centrifugal motion serves to throw out the 
balls, as indicated by the dotted lines J, and this 
action raises the bell-crank lever, and opens the 
throttle valve. 

Numerous types of governors have been con- 
structed, some of which operate by gravity, in 
connection with centrifugal action. Some are 
made with the balls adapted to swing downwardly, 




jFYg. 69._ 2ZM Origina l I njector . 



and thrown back by the action of springs. Others 
have the balls sliding on horizontally-disposed 
arms, and thrown back by the action of springs ; 
and gyroscopic governors are also made which 
are very effective. 

Fly wheel governors are not uncommon, which 
are placed directly on the engine shaft, or placed 
within the fly wheel itself, the latter being a 
well known form for engines which move slowly. 

Injectors. — The Injector is one of the anomalies 
in mechanism. It actually forces water into a 
boiler by the action of the steam itself, against its 



MECHANICAL DEVICES IN POWER 153 

own pressure. It is through the agency of con- 
densation that it is enabled to do this. 

The illustration, Fig. 69, which represents the 
original type of the device, comprises a shell A, 
within which is a pair of conically formed tubes, 
B, C, in line with each other, the small ends of the 
tubes being pointed towards each other, and 
slightly separated. The large end of the conical 
tube C, which points toward the pipe D, which 
leads to the water space of the boiler, has therein 
a check valve E. 

The steam inlet pipe F, has a contracted nozzle 
G, to eject steam into the large end of the conical 
tube B, and surrounding the nozzle F is a cham- 
ber which has a pipe H leading out at one side, 
through which cold water is drawn into the injec- 
tor. 

Surrounding the conical pipes B, C, is a cham- 
ber I, which has a discharge pipe J. The action 
of the device is very simple. When steam is per- 
mitted to flow into the conical tube B, from the 
nozzle G, it passes out through the drain port J, 
and this produces a partial vacuum to form in the 
space surrounding the nozzle G. 

As a result water is drawn up through the pipe 
H, and meeting with the steam condenses the lat- 
ter, thereby causing a still greater vacuum, and 
this vacuum finally becomes so great that, with 



154 MOTORS FOE BOYS 

the inrushing steam, and the rapid movement 
through the conical tubes, past their separated 
ends, a full discharge through the drain J is pre- 
vented. 

As it now has no other place to go the check 
valve E is unseated, and the cold water is forced 
into the boiler through the pipe D, and this ae- 




J^ty 70. In/ecto ?' With 7??x>}/aZZe Ctonibijning 7},te 

tion will continue as long as condensation takes 
place at the nozzle G. 

Many improvements have been made on the 
original form, mostly in the direction of adjust- 
ing the steam nozzle, and to provide the proper 
proportion of flow between the steam and water, 
as this must be adjusted to a nicety to be most 
effective. 

An example of a movable tube which closes the 



MECHANICAL DEVICES IN POWER 155 

outlet to the overflow, is shown in Fig. 70. The 
steam inlet tube A is at one end of the shell, and 
the outlet tube B to the boiler, at the other end, 
and intermediate the two is a tube C, with its open 
flaring end adapted to receive the steam from the 
tube A. This tube is longitudinally-movable, so 
that the controlling lever D may move it to and 
fro. 

A chamber E surrounds the nozzle A, and has 
a water inlet pipe F, while the space G between 
the ends of the pipes B, C, has an outlet H, a 
single check valve I being interposed. In opera- 
tion the tube C may be adjusted the proper dis- 
tance from the end of the pipe B, and when the 
current is once established through the injector, 
the pipe C may be brought into contact with B, 
and thus entirely cut out the movement of the 
water to the overflow. 

Feed Watek Heater. — An apparatus of this 
kind is designed to take the exhaust steam from 
the engine and condense it, and from the con- 
denser it is again returned to the boiler. The 
water thus used over again goes into the boiler at 
a temperature of over 180 degrees, and thus 
utilizes the heat that would otherwise be required 
to raise the temperature of the water from the 
natural heat, say 70, up to that point. 

In Fig. 71 the illustration shows a typical 



156 MOTORS FOR BOYS 

heater, which comprises an outer shell A, each 
end having a double head, the inner head B being 
designed to receive the ends of a plurality of 
horizontally disposed pipes, and the outer heads 
C, separated from the inner head so as to provide 
chambers, one end having one, and the other head 
being provided with two horizontal partitions D, 
so the water may be diverted back and forth 
through the three sets of pipes within the shell. 




a 

JT'ig.TL T^eed tlfofer £ea,U? '. 

The three sets of pipes, E, F, and G, are so 
arranged that they carry the water back and forth 
from one head to the other, and for this purpose 
the water for cooling the steam enters the port 
H at one end, passes through the upper set of 
pipes E to the other end, then back through the 
same set of pipes on the other side of a partition, 
not shown, and back and forth through the two 
lower sets of pipes F, G. 



MECHANICAL DEVICES IN POWER 157 

The steam enters at the port I at the top of 
the shell, and passes down, as it is condensed, be- 
ing discharged at the outlet J. 



CHAPTEE X 

VALVES AND VALVE FITTINGS 

In the use of steam, compressed gas, or any 
medium which must have a controllable flow, 
valves are a necessary element ; and the important 
point is to know what is best adapted for the use 
which is required in each case. 

For this reason one of the best guides is to fully 
understand the construction of each. The follow- 
ing illustrations and descriptions will give a good 
idea of the various types in use. 




*4 
2^g. 78. C7w,ck Value. 

Check Valve. — Fig. 72 shows a longitudinal 
section of a check valve, which is designed to pre- 

158 



VALVES AND VALVE FITTINGS 159 

vent the water from returning or backing up from 
the pressure side. The cylindrical body A is 
threaded at each end, and has an inclined parti- 
tion B therein which has a circular aperture. 
The upper side of the shell has an opening, 



cQa 




T^lg. 7& Gate i/afore . 

adapted to be closed by a cap C, large enough to 
insert the valve D, which is hinged to the upper 
side of the partition. Water or gas is forced in 
through the valve in the direction of the arrow, 
and the hinged valve is always in position to close 
the opening in the partition. 



160 



MOTORS FOR BOYS 



In case the valve should leak it may be readily 
ground by taking the small plug E from the open- 
ing, and with a screw driver, turning the valve, 
and thereby fit it snugly on its seat. 

Gate Valve. — The cylindrical shell A has its 



nnh 




J^ig. 74. GZo&e Ifalve . 

ends internally threaded, and is provided, midway 
between its ends, with a partition wall B, having 
a central aperture. The upper side of the shell 
has an opening to receive the bonnet C, through 
which the valve stem D passes. This stem carries 
at its lower end a gate E which rests against the 
partition B. 



VALVES AND VALVE FITTINGS 161 

The stem D is threaded to screw into the 
threaded bore of the gate. A packing gland F 
surrounds the stem D. It will thus be seen that 
the turning of the stem D draws the gate up 
or down, and thus effects an opening, which pro- 
vides a direct passage for the water through the 
valve body. 

Globe Valve. — A globe valve has the advan- 
tage that the valve is forced against its seat by 
the pressure of the wheel, differing from the gate 
valve, that depends on the pressure of the fluid to 
keep it tight. 

The valve body A has therein a Z-shaped parti- 
tion B, the intermediate, horizontally-disposed 
limb of the partition being directly below the open- 
ing through the body, which is designed to receive 
the bonnet C. 

The bonnet has a central vertical bore, the lower 
end of which is threaded to receive the wheel spin- 
dle. The lower end of the spindle carries the cir- 
cular valve, which is seated in the opening of the 
Z-shaped partition. 

The Corliss Valve. — The valve itself is of the 
rotary type, as shown in Fig. 75, in which the port 
A goes to the cylinder, and B is the passage for 
the steam from the boiler. The cylindrical valve 
body C has within the aperture B a gate D, one 
edge of which rests against the abutment through 



162 MOTOES FOR BOYS 

which the port A is formed, and this gate has 
within it the bar E which is connected with the 
crank outside of the casing. 

The Corliss Valve-Operating Mechanism. — 
As the operation of the valves in the Corliss type 
of engine is so radically different from the or- 
dinary reciprocation engine, a side view of the 
valve grouping and its connecting mechanism are 
shown in Fig. 76. 




2 rr iff. 76. Corli44 ZfeZv& . 

The cylinder has an inlet valve A at each end, 
and an outlet valve B at each end for the discharge 
of the steam. C is a valve rod from the eccentric 
which operates the valves, and D el wrist plate, 
having an oscillatory or rocking motion around its 
center E. The attachments F F, of the steam 
rods, open the inlet ports A A, and G Gr, are the 
attachments of exhaust rods which open and close 
the exhaust valves B B. H H are catches which 
can be unhooked from the stems of the valves A 
by the governor rods J J. 



VALVES AND VALVE FITTINGS 163 

The vertical links K, K are connected at their 
lower ends with the pistons of dash pots, and 
have their upper ends attached to the valve spin- 
dles, and act to close the valves A A when the 
catches H are released by the governor rods J 
by means of the weights of the pistons in the dash 
pots. 




J^ 7 ^. 76. CorlU& Vcdiv - ope7ati?ig 7ftec/iam4??r. 

The dash pots L L act is such a manner as to 
cushion the descent of the links K and thus pre- 
vent undue shock. M is a wrist plate pin by which 
the valve rod C can be released from the wrist 
plate. 

The whole purpose of the mechanism is to pro- 
vide a means for closing the valves which are at 



164 



MOTORS FOR BOYS 



the steam inlet ports, by a sudden action. The 
exhaust valves, on the other hand, are not so 
tripped but are connected directly with the wrist 
plate which drives all four of the valves. 

The wrist plate or spider has a rocking motion, 
being driven by an eccentric rod from the engine- 
shaft. The mechanism thus described gives* a 
variable admission as the load varies, but a con- 




_/%. 77 cdvigle TTaZi/e, . 

stant release of the exhaust and a constant com- 
pression to act as a cushion. 

It gives a high initial pressure in the cylinder, 
and a sharp cut off, hence it is found to be very 
efficient. 

Angle Valve. — One of the most useful is the 
angle valve, which is designed to take the place of 
an angle bend or knee in the line of the piping. 
The mechanism is the same as in the well known 



VALVES AND VALVE FITTINGS 165 

globe valve construction, the bonnet A being on 
a line with one of the right-angled limbs of the 
body. 

The pressure of the fluid should always be on 
the lower side of the valve C, coming from the 
direction of the arrow B, for the reason that 
should the steam pressure be constant on the other 




Hg. 78. Ho-lari / lrtdve T^ig. 70. Ta/o-ajcu/ Rota?:* . 



side, it would be difficult to repack the gland D 
without cutting off the steam from the pipe line. 

Eeferring back to the illustration of the globe 
valve, it will be noticed that the same thing, so 
far as it pertains to the direction of the steam, 
applies in that construction, and a common mis- 
take is to permit the pressure of the steam to be 
exerted so that it is constantly acting against the 
packing of the spindle. 

Eotary Valves. — Two forms of rotary valves 
are shown, one as illustrated in Fig. 78, where the 



166 



MOTORS FOR BOYS 



rotating part, or plug, A has one straight-way 
opening B, which coincides with two oppositely- 
projecting ports C, D. 

The other form, Fig. 79, has an L-shaped open- 
ing E through the rotating plug F, and the casing, 
in which the plug is mounted has three ports, one, 
G, being the inlet, and the other two H, I, at right 
angles for the discharge of the fluid. 

Rotable Engine Valves. — So many different 




JTlp. SO. Motccrif Tbpe . T^ig. 81. Two-wtu Zciariffi pe, 

forms of the rotable valve have been made, that 
it is impossible to give more than a type of each. 
For engine purposes the plugs are usually ro- 
tated in unison with the engine shaft, and a single 
delivery valve of this kind is shown in Fig. 80. 

This has three ports in the casing, namely the 
inlet port A, and two outlet ports C, D. The plug 
has a curved cut out channel E, and this extends 
around the plug a distance equal to nearly one- 



VALVES AND VALVE FITTINGS 167 

half of the circumference, so that the steam will 
be diverted into, say, B, for a period equal to one- 
quarter turn of the plug, and then into port C, for 
the same length of time. 

Fig. 81 shows a valve which has a double action. 
The plug G has two oppositely-disposed curved 
channels, H, I, and the casing has a single inlet 
port J, and two oppositely-disposed outlet ports 
K, L. 





T^to. 82. Buttjerfh/Throm . TYq. dS.^rwle Throitte . 



When the plug turns the* port L serves to con- 
vey the live steam to the engine, while the other 
port K at the same time acts as the exhaust, and 
this condition is alternately reversed so that L 
acts as the discharge port. 

Throttle Valves. — The throttle valves here 
illustrated are those used in connection with 
gasoline engines. The best known is the Butter-fly 
valve, shown in Fig. 82, and this is also used as a 



168 



MOTORS FOR BOYS 



damper, for regulating the draft in furnaces and 
stoves. 

This type is made in two forms, one in which the 
two wings of the valve are made to swing up or 
down in unison, and the other, as illustrated, 
where the disk A is in one piece, and turns with the 
spindle B to which it is fixed. 

In Fig. 83 the wing C is curved, so that by swing- 




'Ftg.84. dlvcLe. Throttle. , l^zg. 85. 7h/o - 6lteeT/?jom . 

ing it around the circle, the opening of the dis- 
charge pipe D is opened or closed. 

Another design of throttle is. represented in 
Fig. 84. One side of the pipe A has a lateral ex- 
tension B, which is double, so as to receive therein 
a sliding plate C, which is easily controllable from 
the outside. 

Fig. 85 shows a form of double sliding plate, 
where the double lateral extensions project out in 
opposite directions, as at D, D, and within these 
extensions are sliding plates which are secured 
together in such a way that as one is pushed in 



VALVES AND VALVE FITTINGS 169 



the other also moves in, and thus acts in unison 
to close or to open the space between them. It is 
the most perfect form of throttle valve, as it 
causes the gases to open directly into the center 
of the outgoing pipe. 

Blow-off Valves. — The illustration shows a 
type of valve which is used on steamboats and very 
largely on farm boilers throughout the country. 




JFig. 86. mow -orr iralire . 

The pipe A from the boiler has cast therewith, or 
otherwise attached, a collar B, which has a stand- 
ard C projecting upwardly at one side, to the 
upper end of which is hinged a horizontal lever D, 
which has a weight at its other end. 

The upper end of the pipe has a conically- 
ground seat, to receive a conical valve E, the stem 
of which is hinged, as at F, to the level. The 
weight may be adjusted to the pressure desired 
before blowing out and the only feature in this 
type of valve is the character of the valve seat, 



170 



MOTOBS FOE BOYS 



which is liable, through rust, and other causes, to 
leak. 

Pop, or Safety Valve. — As it has been found 
more desirable and practical to use a form of 
valve which is not liable to deterioration, and also 




Z^ig. 87. Safety Top Valve. 

to so arrange it that it may be manually opened, 
the Safety Pop valve was devised. 

This is shown in Fig. 87, in which the valve 
seat base A, which is attached to the top of the 
boiler, has a cup-shaped outlet B, that is screwed 
to it, and this carries a lever C, by means of 
which the valve may be manually opened. 



VALVES AND VALVE FITTINGS 171 

A vertical shell D is attached to the cup-shaped 
portion, and this has a removable cap E. The 
valve F is seated within a socket in the base, and 
has a disk head, to receive the lower end of a 
coiled spring G-. 

The spring is supported in position by a stem 
H which extends down from the head, and an ad- 
justing nut I serves to regulate the pressure de- 
sired before the steam in the boiler can act. 



CHAPTEE XI 

CAMS AND ECCENTRICS 

More or less confusion arises from the terms 
cams and eccentrics. A cam is a wheel which 
may be either regular in shape, like a heart- 
wheel, or irregular, like a iviper-wheel. 

The object in all forms of cams is to change 
motion from a regular into an irregular, or re- 
versely, and the motion may be accelerated or re- 
tarded at certain points, or inverted into an in- 
termittent or reciprocating movement, depend- 
ent on the shape of the cam. 

A cam may be in the shape of a slotted or 
grooved plate, like the needle bar of a sewing ma- 
chine, where a crank pin works in the slot, and 
this transmits an irregular vertical movement to 
the needle. 

A cam may have its edge provided with teeth, 
which engage with the teeth of the engaging 
wheel, and thus impart, not only an irregular mo- 
tion but also a turning movement, such forms be- 
ing largely used to give a quickly rising or fall- 
ing motion. 

172 



CAMS AND ECCENTRICS 



173 



What are called iviper ivheels are designed to 
give an abrupt motion and such types are used in 
trip hammers, and to operate stamp mills. In 
harvesters, printing presses, sewing machines, 
and mechanism of that type, the cam is used in 
a variety of forms, some of them very ingenious 
and complicated. 

Cams are also used for cutting machines, or in 





tracing apparatus where it would be impossible to 
use ordinary mechanism. All such forms are spe- 
cial, requiring care and study to make their move- 
ments co-relate with the other parts of the mech- 
anism that they are connected up with. 

Simple Cams. — Fig. 88 shows a form of the 
most simple character, used, with some modifica- 
tions, to a larger extent than any other. It is 
called the heart shaped cam, and is the regular 
type. 



174 MOTOKS FOR BOYS 

Fig. 89 is an elliptical cam, which is also 
regular. What is meant by regular is a form that 
is the same in each half portion of its rotation. 

Fig. 90 is a double elliptic, which gives a 
regular movement double the number of times of 
that produced by the preceding figure, and the 
differences between the measurements across the 
major and minor axes may vary, relatively, to any 
extent. 

§> 

Wiper Wheels. — Wiper wheels are cams which 
give a quick motion to mechanism, the most com- 
mon form being the single wiper, as shown in 
Fig. 91. 

The double wiper cam, Fig. 92, has, in some 
mechanism, a pronounced difference between the 
lengths of the two fingers which form the wipers. 

The form of cam shown in Fig. 93 is one much 
used in iron works for setting in motion the tilt 
hammer. Only three fingers are shown, and by 
enlarging the cam at least a dozen of these pro- 
jecting points may be employed. 

Cam Sectors. — Fig. 94 shows a type of cam 




CAMS AND ECCENTRICS 



175 



which is designed for rock shafts. The object 
of this form of cam is to impart a gradually in- 
creasing motion to a shaft. Assuming that A is 
the driving shaft, and B the driven shaft, the 
cam C, with its short end D, in contact with the 




^ig.^. Cam 6eetor. 




jF'ig. 93. Groofod Cam . J^lg. <96. Tiecwocai/^/hoiwn . 

long end E of the sector F, causes the shaft B to 
travel at a more accelerated speed as the other 
edges G, H, approach each other. 

Cylinder Cam. — Fig. 95 shows one form of 
cylinder A with a groove B in it, which serves 



176 



MOTOES FOR BOYS 



as a means for moving a bar C back and forth. 
The bar has a projecting pin D, which travels in 
the groove. 

This form of movement may be modified in 
many ways, as for instance in Fig. 96, where the 
drum E has a sinuons groove F to reciprocate a 
bar G to and fro, the groove being either regular, 
so as to give a continuous back and forth move- 




T^ig. 97. Pi votedi T^ollourer for Cam . 

ment of the bar ; or adapted to give an irregular 
motion to the bar. 

Double Cam Motion. — Cams may also be so 
arranged that a single one will produce motions 
in different directions successively, as illustrated 
in Fig. 97. The horizontal bar A, hinged at B 
to the upper end of a link C, has its free end rest- 
ing on the cam D. 

The arm A has also a right-angled arm E ex- 
tending downwardly, and is kept in contact with 



CAMS AND ECCENTRICS 177 

the cam by means of a spring F. Connecting 
rods G, H, may be hinged to the arm E and bar 
A, respectively, so as to give motion to them in 
opposite directions as the cam revolves. 

Eccentrics. — An eccentric is one in which the 
cam or wheel itself is circular in form, but is 
mounted on a shaft out of its true center. An ec- 
centric may be a cam, but a cam is not always ec- 

Fig98£ccen/ric[ ^ I 




J^ig. 99. J57cce?ttric Cam . 



centric in its shape. The term is one in direct 
contrast with the word eccentric. 

Fig. 98 shows the wheel, or the cam, which is 
regular in outline, that is circular in form, but 
is mounted on the shaft out of its true center. In 
this case it is properly called an eccentric cam but 
in enginery parlance it is known as the eccentric, 
as represented in Fig. 99. 

Triangularly-Formed Eccentric. — Fig. 100 
illustrates a form of cam which has been used on 
engines. The yoke A being integral with the bar 
B, gives a reciprocating motion to the latter, and 



178 



MOTORS FOE BOYS 



the triangular form of the cam C, which is 
mounted on the shaft D, makes a stop motion at 
each half-revolution, then produces a quick mo- 




2^.100. T 7 na?wu2a77y - rorm£d, JZccenfofc . 



tion, and a slight stop only, at the half turn, and 
the return is then as sudden as the motion in the 
other direction. 



CHAPTER XII 

GEARS AND GEARING 

For the purpose of showing how motion may 
be converted from a straight line or from a cir- 
cular movement into any other form or direction, 
and how such change may be varied in speed, or 
made regular or irregular, the following examples 
are given, which may be an aid in determining 
other mechanical devices which can be specially 
arranged to do particular work. 

While cams and eccentrics may be relied on to 
a certain extent, there are numerous places where 
the motion must be made positive and continued. 
This can be done only by using gearing in some 
form, or such devices as require teeth to transmit 
the motion from one element to the other. 

The following illustrations do not by any means 
show all the forms which have been constructed 
and used in different machines, but they have been 
selected as types merely, in order to give the sug- 
gestions for other forms. 

Racks and Pinions. — The rack and pinion is the 
most universal piece of mechanism for changing 

179 



180 MOTOKS FOR BOYS 

motion. Fig. 101 illustrates it in its most sim- 
ple form. When constructed in the manner 
shown in this figure it is necessary that the shaft 
which carries the pinion shall have a rocking mo- 
tion, or the rack itself must reciprocate in order 
to impart a rocking motion to the shaft. 





Fig. J 01 RackandTinwn . TYg. JO 2. Rack * 



This is the case also in the device shown in Fig. 
102, where two rack bars are employed. A 
study of the cams and eccentrics will show that 
the transference of motion is limited, the dis- 
tances being generally very small; so that the 
rack and pinions add considerably to the scope 
of the movement. 

The Mangle Rack. — The device called the man- 
gle rack is resorted to where a back and forth, or 



GEAES AND GEARING 



181 



a reciprocating movement is to be imparted to an 
element by a continuous rotary motion. 

The plain mangle racks are shown in Figs. 103 
and 104, the former of which has teeth on the in- 
side of the opposite parallel limbs, and the latter, 




IPig. 703. Main Tnan gle Hack . 




JTzgJM. ?7Za,?ig lo RcLo7cMoito?t . 




J^tg. ?05. e/HtzTnctte, Ci7 -cula7 ' Tftotion. 



Fig. 104, having teeth not only on the parallel 
sides, but also around the circular parts at the 
ends. 

This form of rack may be modified so that an 
alternate circular motion will be produced dur- 



182 



MOTOES FOR BOYS 



ing the movement of the rack in either direction. 
Fig. 105 is such an instance. A pinion within 
such a rack will turn first in one direction, and 
then in the next in the other direction, and so on. 

If the rack is drawn back and forth the motion 
imparted to the pinion will be such as to give a 
continuous rocking motion to the pinion. 

Controlling the Pinion. — Many devices have 
been resorted to for the purpose of keeping the 




T^g. f06. Conirolli7ig Pinion forTftcwgfoRacfc 

pinion in engagement with the teeth of the mangle 
rack. One such method is shown in Fig. 106. 

The rack A has at one side a plate B, within 
which is a groove C, to receive the end of the shaft 
D, which carries the pinion E. As the mangle rack 
moves to such a position that it reaches the end 
of the teeth F on one limb, the groove C diverts 
the pinion over to the other set of teeth Gr. 

All these mangle forms are substitutes for 
cranks, with the advantage that the mangle gives 
a uniform motion to a bar, whereas the to and fro 



GEAES AND GEARING 



183 



motion of the crank is not the same at all points of 
its travel. 

Examine the diagram, Fig. 107, and note the 
movement of the pin A which moves along the 
path B. The crank C in its turning movement 
around the circle D, moves the pin A into the dif- 
ferent positions 1, 2, 3, etc., which correspond 
with the positions on the circle D. 

The Deax> Centers. — There is also another ad- 




/ k, 8 **p $ 6 76 1 £ 6 <4 5 6 76 

-T 7 "^. 70Z Illu6J7'ati?ig C?an/c-p in fooi/ement r 

vantage which the rack possesses. Where re- 
ciprocating motion is converted into circular mo- 
tion, as in the case of the ordinary steam engine, 
there are two points in the travel of a crank where 
the thrust of the piston is not effective, and that 
is at what is called the dead, centers. 

In the diagram, Fig. 108, the ineffectiveness of 
the thrust is shown at those points. 

Let A represent the piston pushing in the direc- 
tion of the arrow B against the crank C. When 
in this position the thrust is the most effective, 
and through the arc running from D to E, and 



184 



MOTORS FOR BOYS 



from H to Gr, the cylinder does fully four-fifths of 
the work of the engine. 

While the crank is turning from Gr to D, or 




JTlp. /OS. Fhe Dead Cento : 

from I to J, and from K to L, no work is done 
which is of any value as power. 

If, therefore, a mangle bar should be used in- 
stead of the crank it would add greatly to the ef- 
fectiveness of the steam used in the cylinder. 




T^ig. 709. Ciank Tflotwn -Suddtifafe. 

Crank Motion Substitute. — In Fig. 109 the 
pinion A is mounted so that its shaft is in a verti- 



GEAES AND GEARING 185 

cal slot B in a frame C. The mangle rack D, in 
this case, has teeth on its onter edge, and is made 
in an elongated form. The pinion shaft moves up 
and down the slot and thus guides the pinion 
around the ends of the rack. 

Mangle Wheels. — The form which is the most 
universal in its application is what is called the 



CO-*? 




a 

T^ig. //O. faanale Wheel . 

mangle wheel. In Fig. 110 is shown a type 
wherein the motion in both directions is uniform. 
Mangle wheels take their names from the iron- 
ing machines called mangles. In apparatus of 
this kind the movement back and forth is a slow 
one, and the particular form of wheels was made 
in order to facilitate the operation of such ma- 
chines. In some mangles the work between the 
rollers is uniform back and forth. In others the 



186 



MOTORS FOR BOYS 



work is done in one direction only, requiring a 
quick return. 

In still other machines arrangements are made 
to provide for short strokes, and for different 
speeds in the opposite directions, under certain 
conditions, so that this requirement has called 




jf^Yg. ///. Quick Tietum ?/iotio?i . 



forth the production of many forms of wheels, 
some of them very ingenious. 

The figure referred to has a wheel A, on one 
side of which is a peculiarly-formed continuous 
slot B, somewhat heart-shaped in general out- 
line, one portion of the slot being concentric with 
the shaft 0. 

Within the convolutions of the groove is a set 
of teeth D, concentric with the shaft C. The 
pinion E, which meshes with the teeth D, has the 
end of its shaft F resting in the groove B, and it 
is also guided within a vertical slotted bar G. 



GEAES AND GEAEING 



187 



The pinion E, therefore, travels over the same 
teeth in both directions, and gives a regular to and 
fro motion. 

Quick Return Motion. — In contradistinction 
to this is a wheel A, Fig. Ill, which has a pair 
of curved parallel slots, with teeth surrounding 




-i^^ //£. zrfccete? cited, Circular footion. 



the slots. When the wheel turns nearly the en- 
tire revolution, with the pinion in contact with 
the outer set of teeth, the movement transmitted 
to the mangle wheel is a slow one. 

When the pinion arrives at the turn in the 
groove and is carried around so the inner teeth 
are in engagement with the pinion, a quick return 
is imparted to the wheel. 

Accelerated Motion. — Aside from the rack and 
mangle type of movement, are those which are 



188 



MOTORS FOR BOYS 



strictly gears, one of them being a volute form, 
shown in Fig. 112. This gear is a face plate A, 
which has teeth B on one face, which are spirally- 
formed around the plate. These mesh with a 
pinion C, carried on a horizontal shaft D. This 




JFfy //S. Quick Jjetura Gearing . 



shaft is feathered, as shown at E, so that it will 
carry the gear along from end to end. 

The gear has cheek-pieces F to guide it along 
the track of teeth. As the teeth, approach the 
center of the wheel A, the latter impart a motion 
to the gear which is more than twice the speed that 
it receives at the starting point, the speed being 
a gradually increasing one. 

Quick Return Gearing. — Another much more 
simple type of gearing, which gives a slow for- 



GEAES AND GEARING 189 

ward speed and a quick return action, is illus- 
trated in Fig. 113. A is a gear with internal teeth 
through one half of its circumference, and its hub 
B has teeth on its half which is opposite the teeth 
of the rim. 

A pinion C on a shaft D is so journaled that 
during one half of the rotation of the wheel A, 




7^//^. derail Gearin p. 



it engages with the rim teeth, and during the 
other half with the hub teeth. As the hub B 
and gear C are the same diameter, one half turn 
of the pinion C will give a half turn to the wheel 
A. 

As the rim teeth of the wheel A are three times 
the diameter of the pinion C, the latter must turn 
once and a half around to make a half revolution 
of the wheel A. 

Scroll Gearing. — This is a type of gearing 



190 MOTORS FOR BOYS 

whereby at the close of each revolution the speed 
may be greater or less than at the beginning. It 
comprises two similarly-constructed gears A, B, 
each with its perimeter scroll-shaped, as shown. 
The diagram shows their positions at the begin- 
ning of the rotation, the short radial limb of one 
gear being in line with the long limb of the other 
gear, hence, when the gears rotate, their speeds 
relative to each other change, being constantly 
accelerated in one or decreased in the other. 



CHAPTER XIII 

SPECIAL TYPES OF ENGINES 

In describing various special types of motors, 
attention is first directed to that class which de- 
pend on the development of heat in various gases, 
and this also necessitates some explanation of ice- 
making machinery, and the principles underlying 
refrigeration. 

It is not an anomaly to say that to make ice 
requires heat. Ice and boiling water represent 
merely the opposites of a certain scale in the con- 
dition of matter, just as we speak of light and 
darkness, up and down, and like expressions. 

We are apt to think zero weather is very cold. 
Freezing weather is a temperature of 32 degrees. 
At the poles 70 degrees below have been recorded. 
In interstellar space, — that is, the region between 
the planets, it is assumed that the temperature is 
about 513 degrees Fahrenheit, below zero, called 
absolute zero. 

The highest heat which we are able to produce 
artificially, is about 10,000 degrees by means of 
the electric arc. We thus have a range of over 

191 



192 MOTORS FOR BOYS 

10,500 degrees of heat, but it is well known that 
heat extends over a much higher range. 

Assuming, however, that the figures given rep- 
resent the limit, it will be seen that the difference 
between ice and boiling water, namely, 180 de- 
grees, is a very small range compared with the 
temperatures referred to. 

In order to effect this change power is neces- 
sary, and power requires a motor of some kind. 
Hence it is, that to make a lower temperature, a 
higher degree of heat is necessary, and in the 
transit between a high and a low temperature, 
there is considerable loss in this respect, as in 
every other phase of power mechanism, as has 
been pointed out in a previous chapter. 

In order that we may clearly understand 
the phenomena of heat and cold, let us take a re- 
ceiver which holds a cubic foot of gas or liquid, 
and exhaust all the air from it so the vacuum will 
be equivalent to the atmospheric pressure, namely, 
14.7 pounds per square inch. 

Alongside is a small vessel containing one cubic 
inch of water, which is heated so that it is con- 
verted into steam, and is permitted to exhaust 
into the receiver. When all the water is con- 
verted into steam and fills the receiver we shall 
have the same pressure inside the receiver as on 
the outside. 



SPECIAL TYPES OF ENGINES 193 

It will be assumed, of course, that there has 
been no loss by condensation, and that the cubic 
inch of water has been expanded 1700 times by 
its conversion into steam. 

In a short time the steam will condense into 
water, and we now have, again, a partial vacuum 
in the receiver, due, of course, to the change in 
bulk from steam to water. Each time the liquid 
is heated it produces a pressure, and the pres- 
sure indicates the presence of heat; and when- 
ever it cools a loss of pressure is indicated, and 
that represents cold, or the opposite of heat. 

Now, putting these two things together, we get 
the starting point necessary in the development of 
power. Let us carry the experiment a step fur- 
ther. Liquids are not compressible. Gases are. 
The first step then is to take a gas and compress 
it, which gives it an increase of heat temperature, 
dependent on the pressure. 

If the same receiver is used, and say, two at- 
mospheres are compressed within it, so that it has 
two temperatures, and the exterior air cools it 
down to the same temperature of the surrounding 
atmosphere, we are ready to use the air within 
to continue the experiment. 

Let us convey this compressed gas through 
pipes, and thus permit it to expand; in doing so 
the area within the pipes, which is very much 



194 MOTORS FOR BOYS 

greater than that of the receiver, grows colder, 
due to the rarefied gases within. Now bearing in 
mind the previous statement, that loss of pres- 
sure indicates a lowering of temperature, we can 
see that first expanding the gas, or air, by heat, 
and then allowing it to cool, or to produce the 
heat by compressing it, and afterwards permit- 
ting it to exhaust into a space which rarefies it, 
will make a lower temperature. 

It is this principle which is used in all re- 
frigerating machines, whereby the cool pipes ex- 
tract the heat from the surrounding atmosphere, 
or when making ice, from the water itself, and 
this temperature may be lowered to any extent de- 
sired, dependent on the degree of rarefaction pro- 
duced. 

Let us now see how this applies to the genera- 
tion of power in which we are more particularly 
interested. 

All liquids do not evaporate at the same tem- 
perature as water. Some require a great deal 
more than 212 degrees.; others, like, for instance, 
dioxide-of-carbon, will evaporate at 110 degrees, 
or about one half the heat necessary to turn 
water into steam. 

On the other hand, all gases act alike so far as 
their heat absorption is concerned, so that by 
using a material with a low evaporative unit, less 



SPECIAL TYPES OF ENGINES 195 

fuel will be required to get the same expansion, 
which means the same power. 

To illustrate this, let us assume that we have 
equal quantities of water, and of dioxide-of-car- 
bon, and that is to be converted into a gas. It will 
take just double the amount of fuel to convert the 
water into a gaseous state. As both are now in 
the same condition, the law of heat absorption is 
the same from this time on. 

The dioxide-of-carbon engine is one, therefore, 
which uses the vapor of this material, which, after 
passing through the engine, is condensed and 
pumped back to the boiler to be used over and 
over. 

In like manner, also, ether, which has a low 
point of vaporization, is used in some engines, 
the principle being the same as the foregoing 
type. 

Rotary Engines. — Many attempts have been 
made to produce a rotary type of steam engine, 
and also to adapt it for use as an internal com- 
bustion motor. 

The problem is a complicated one for the fol- 
lowing reasons: First, it is difficult to provide 
for cut-off and expansion. A rotating type, to 
be efficient, must turn at a high rate of speed, 
and this makes the task a more trying one. Sec- 
ond, the apparent impossibility of properly pack- 



196 



MOTOKS FOR BOYS 



ing the pistons. The result is a waste of steam, 
or the gas used to furnish the power. Third, the 
difficulty in providing a suitable abutment so as 
to confine the steam or gas, and make it operative 
against the piston. 




JT r ig.//& &impfcjRofaryttzgzne. 



In Fig. 115 is shown a type of rotary which 
is a fair sample of the characteristics of all mo- 
tors of this form. It comprises an outer cylin- 
drical shell, or casing, A, having a bore through 
the ends, which is above the true center of the 
shell, to receive a shaft B. 

This shaft carries a revolving drum C of such 



SPECIAL TYPES OF ENGINES 197 

dimensions that it is m contact with the shell at 
its upper side only, as shown at D, leaving a chan- 
nel E around the other portions of the drum. 

The steam inlet is at F, which is one-eighth of 
the distance around the cylinder, and the exhaust 
is at Gr, the same distance from the- point D, on 
the other side. The inlet and* the outlet pipes 
are, therefore, at the contracted parts of the 
channel. 

The drum has a pair of radially-movable blades 
H H', which may move independently of each 
other, but usually they are connected together, 
thus dispensing with the use of any springs to 
keep their ends in contact with the shell. 

When steam enters the inlet F the pressure 
against the blade H drives the drum to the right, 
and the drum and shell, by contacting at D, form 
an abutment. Each charge of steam drives the 
drum a little over a half revolution. 

A great deal of ingenuity has been exercised to 
arrange this abutment so that the blades may pass 
and provide a steam space for a new supply of 
steam. In certain types a revolving abutment is 
formed, as shown, for instance, in Fig. 116. 

The shell A, in this case, has two oppositely-dis- 
posed inlet and outlet ports, B, C, respectively, 
and between each set of ports is a revolving gate, 
formed of four wings D, mounted on a shaft E, 



198 



MOTORS FOR BOYS 



in a housing outside of the circular path F, be- 
tween the drum G and shell A. 

The drum G is mounted on a shaft H which is 
centrally within the shell, and it has two op- 
positely-projecting rigid blades I. When steam 




J^ff* //6. 7?ouHe feed Ttotiztyttigine. 

enters either of the stfpply ports B, the drum is 
rotated, and when the blades reach the revolving 
gates, the latter are turned by the blades, or, they 
may be actuated by mechanism connected up 
with the driving shaft. 

Cajloric Engine. — This is an engine which is 
dependent on its action upon the elastic force of 



SPECIAL TYPES OF ENGINES 199 

air which is expanded by heat. The cylinder of 
such a motor has means for heating it, and thus 
expanding the air, and a compressor is usually 
employed which is operated by the engine itself, 
to force compressed air into the cylinder. 

It is not an economical engine to work, but it 
is frequently used in mines, in which case the 
compressor is located at the surface, and the 
engine operated within the mine, thus serving a 
double purpose, that of supplying power, and also 
furnishing the interior with fresh air. 

All engines of this character must run at a slow 
speed, for the reason that air does not absorb 
heat rapidly, and sufficient time must be given 
to heat up and expand the air, so as to make it 
effective. 

Adhesion Engine. — A curious exhibition of the 
action of a gas against a solid, is shown in what 
is called an Adhesion Engine. Fig. 117 shows its 
construction. A plurality of disks A are mounted 
on a shaft B, these disks being slightly separated 
from each other. 

The steam discharge pipe C is flattened at its 
emission end, as shown at D, so the steam will 
contact with all the disks. The steam merely con- 
tacts with the sides of the disks, the movement of 
the steam being substantially on the plane of the 
disks themselves, and the action sets up a rapid 



200 



MOTORS FOR BOYS 



rotation, and develops a wonderful amount of 
power. 

It will be understood that the disks are en- 
closed by a suitable casing, so that the steam is 
carried around and discharged at a point about 




three quarters of the distance in the circumfer- 
ence. 

This motor is given to illustrate a phase of the 
subject in the application of a motor fluid, like 
steam, or heated gases, that shows great possibili- 
ties. It also points out a third direction in which 
an expansive fluid may be used. 

Thus the two well-known methods, namely, 
pressure, and impact forces, may be supplemented 
by the principle of adhesion, in which the expan- 



SPECIAL TYPES OF ENGINES 201 

sive force of a gas, passing alongside of and in 
contact with a plain surface, may drag along the 
surface in its train. 

Such an exhibition of force has an analogy in 
nature by what is known as capillary attraction, 
which shows adhesion. For instance, sap flowing 
up the pores of trees, or water moving along the 
fibers of blotting paper, illustrates movement of 
liquids when brought into contact with solids. 



CHAPTER XIV 

ENGINERY IN THE DEVELOPMENT OF THE HUMAN RACE 

The energy of a nation may be expressed by 
its horse power. It is not numbers, or intellect, 
or character, or beliefs that indicate the prog- 
ress of a people in a material sense. 

It is curious how closely related enginery is with 
the advancement of a people. Nothing can be 
more striking to illustrate this than railroads as 
a feature of development in any country. 

Power in Transportation. — Without the con- 
struction and maintenance of mechanical power, 
railroads would be impossible. To be able to 
quickly and cheaply move from place to place, is 
the most important factor in human life. The 
ability of people to interchange commodities, and 
to associate with others who are not in their own 
intimate community, are the greatest civilizing 
agencies in the world. 

Power vs. Education and the Arts. — Educa- 
tion, the cultivation of the fine arts, and the desire 
for luxuries, without the capacity for quickly in- 
terchanging commodities and to intermingle with 

202 



DEVELOPMENT OF HUMAN RACE 203 

each other, are ineffectual to advance the interests 
of any nation, or to maintain its prosperity. 

Lack of Power in the Ancient World. — The 
Greeks and the Romans had a civilization which 
is a wonder even to the people of our day. They 
had the arts and architecture which are now re- 
garded as superb and incomparable. They had 
schools of philosophy and academies of learning; 
their sculpture excites the admiration of the 
world; and they laid the foundation theories of 
government from which we have obtained the 
basis of our laws. 

The Early Days of the Republic. — When our 
forefathers established the Republic there were 
many misgivings as to the wisdom of including 
within its scope such a large area as the entire 
Atlantic seacoast. From Maine to Florida the 
distance is 1250 miles ; and from New York to the 
Mississippi 900 miles, comprising an area of 
1,200,000 square miles. 

How could such an immense country ever hold 
itself together? It was an area nearly as large as 
that controlled by Rome when at the height of 
her power. If it was impossible for the force 
of Roman arms to hold such a region within its 
control, how much more difficult it would be for 
the Colonies to expect cohesion among their scat- 
tered peoples. 



204 MOTORS FOR BOYS 

Lack of Cohesiveness in a Country Without 
Power. — Those arguments were based on the 
knowledge that every country in ancient times 
broke apart because there was no unity of inter- 
est established, and because the different parts of 
the same empire did not become acquainted or 
associated with each other. 

The Railroad as a Factor in Civilization. — 
The introduction of railroads, by virtue of mo- 
tive power, changed the whole philosophy of his- 
tory in this respect. EVen in our own country 
an example of the value of railroads was shown 
in the binding effect which they produced between 
the East and the West prior to the Civil War. 

All railroads, before that period, ran east and 
west. Few extended north and south. It is pop- 
ularly assumed that the antagonism between the 
North and the South grew out of the question of 
slavery. This is, no doubt, largely so, as an im- 
mediate cause, but it was the direct cause which 
prevented the building of railroads between the 
two sections. 

It simply reenforces the argument that the mo- 
tor, the great power of enginery, was not brought 
into play to unite people who were antagonistic, 
and who could not, due to imperfect communica- 
tion, understand each other. 

To-day the United States contains an area 



DEVELOPMENT OF HUMAN RACE 205 

nearly as great as the whole of Europe, including 
Russia, with their twenty, or more, different gov- 
ernments. Here we have a united country, with 
similar laws, habits, customs and religions 
throughout. In many of those foreign countries 
the people of adjoining provinces are totally un- 
like in their characteristics. 

It has been shown that wherever this is the case 
it is due to lack of quick and cheap intercommuni- 
cation. 

The Wonderful Effects of Power. — This 
remarkable similarity in the conditions of the 
people throughout the United States is due to the 
railroads, that great personification of power, not- 
withstanding the diverse customs and habits of 
the people which daily come to our shores and 
spread out over our vast country. 

It has unified the people. It has made San 
Francisco nearer to New York than Berlin was 
to Paris in the time of Napoleon. The people 
in Maine and Texas are neighbors. The results 
have been so far reaching that it has given stabil- 
ity to the government greater than any other 
force. 

But there is another lesson just as wonderful 
to contemplate. England has an area of only 
about 58,000 square miles, about the same size as 
either Florida, Illinois, or Wisconsin. 



206 MOTORS FOE BOYS 

England as a User of Power. — The enginery 
within her borders is greater than the combined 
energy of all the people on the globe. Through 
the wonderful force thus set in motion by her 
remarkable industries she has become the great 
manufacturing empire of the world, and has called 
into existence a carrying fleet of vessels, also con- 
trolled by motors, so stupendous as to be beyond 
belief. 

We may well contemplate the great changes 
which have been brought about by the fact that 
man has developed and is using power in every 
line of work which engages his activities. 

The Automobile. — He does not, in progressive 
countries, depend on the muscle of the man, or on 
the sinews of animals. These are too weak and 
too slow for his needs. Look at the changes 
brought about by the automobile industry within 
the past ten years. What will the next century 
bring forth! 

Artificial power, if we may so term it, is a late 
development. It is very young when compared 
with the history of man. 

High Character of Motor Study. — The study 
of motors requires intellect of a high order. It 
is a theme which is not only interesting and at- 
tractive to the boy, but the mastery of the sub- 



DEVELOPMENT OF HUMAN EACE 207 

ject in only one of its many details, opens up a 
field of profit and emoluments. 

The Unlimited Field of Power. — It is a field 
which is ever broadening. The student need not 
fear that competition will be too great, or the op- 
portunities too limited, and if these pages will 
succeed, in only a small measure, in teaching the 
fundamental ideas, we shall be repaid for the 
efforts in bringing together the facts presented. 



CHAPTER XV 

THE ENEKGY OF THE SUN, AND HOW 
HEAT IS MEASTJKED 

In the first chapter we tried to give a clear view 
of the prime factors necessary to develop motion. 
The boy must thoroughly understand the princi- 
ples involved, before his mind can fully grasp the 
ideas essential in the undertaking. . 

While the steam engine has been the prime 
motor for moving machinery, it is far from being 
efficient, owing to the loss of two-thirds of the 
energy of the fuel in the various steps from the 
coal pile to the turning machinery. 

First, the fuel is imperfectly consumed, the 
am'ount of air admitted to the burning mass being 
inadequate to produce perfect combustion. 

Second, the mechanical device, known as the 
boiler, is not so constructed that the water is able 
to completely absorb the heat of the fuel. 

Third, the engine is not able to continuously 
utilize the expansive force of the steam at every 
point in the revolution of the crank-shaft. 

Fourth, radiation, the dissipation of heat, and 
condensation, are always at work, and thus de- 
tract from the efficiency of the engine. 

208 



THE ENEEGY OF THE SUN 209 

The gasoline motor, the next prime motor of 
importance, is still less efficient in point of fuel 
economy, since less than one-third of the fuel is 
actually represented in the mechanism which it 
turns. 

The production of energy, in both cases, in- 
volves the construction of a multiplicity of devices 
and accessories, many of them difficult to make 
and hard to understand. 

To produce power for commercial purposes, at 
least two things are absolutely essential. First, 
there must be uniformity in the character of the 
power produced ; and, second, it must be available 
everywhere. 

Water is the cheapest prime power, but its use 
is limited to streams or moving bodies of water. 
If derived from the air currents no dependence 
can be placed on the regularity of the energy. 

Heat is the only universal power on the globe. 
The sun is the great source of energy. Each year 
it expends in heat a sufficient force to consume 
over sixty lumps of coal, each equal to the weight 
of the earth. 

Of that vast amount the earth receives only a 
small part, but the portion which does come to 
it is equal to about one horse power acting con- 
tinously over every thirty square feet of the sur- 
face of our globe. 



210 MOTORS FOR BOYS 

The great problem, in the minds of engineers, 
from the time the steam engine became a factor, 
was to find some means whereby that energy 
might be utilized, instead of getting it by way of 
burning a fuel. 

One of the first methods proposed was to use 
a lens or a series of mirrors, by means of which 
the rays might be focused on some object, or 
materials, and thus produce the heat necessary 
for expansion, without the use of fuel. 

Wonderful results have been produced by this 
method ; but here, again, man meets with a great 
obstacle. The heat of the sun does not reach us 
uniformly in its intensity ; clouds intervene and cut 
off the rays ; the seasons modify the temperature ; 
and the rotation of the globe constantly changes 
the direction of the beams which fall upon the lens. 

The second method consists in using boxes cov- 
ered with glass, the interior being blackened to 
absorb the heat, and by that means transmit the 
energy to water, or other substances adapted to 
produce the expansive force. 

Devices of this character are so effective that 
temperatures much above the boiling point of 
water have been obtained. The system is, how- 
ever, subject to the same drawbacks that are urged 
against the lens, namely, that the heat is irregu- 
lar, and open to great variations. 



THE ENERGY OF THE SUN 211 

These defects, in time, may be overcome, in 
conserving the force, by using storage batteries, 
but to do so means the change from one form of 
energy to another, and every change means loss 
in power. 

The great problem of the day is this one of the 
conversion of heat into work. It is being done 
daily, but the boy should understand that the 
direct conversion is what is required. For in- 
stance, to convert the energy, which is in coal, 
into the light of an electric lamp, requires at least 
five transformations in the form of power, which 
may be designated as follows : 

1. The burning of the coal. 

2. The conversion of the heat thus produced 
into steam. 

3. The pressure of the steam into a continuous 
circular motion in the steam engine. 

4. The circular motion of the steam engine into 
an electric current by means of a dynamo. 

5. The change from the current form of energy 
to the production of an incandescent light in the 
lamp itself, by the resistance which the carbon 
film offers to the passage of the current. Should 
an inventor succeed in eliminating only one of 
the foregoing steps, he would be hailed as a gen- 
ius, and millions would not be sufficient to com- 
pensate the fortunate one who should be able 



212 MOTORS FOE BOYS 

to dispense with three of the steps set forth. 

The Measukement of Heat. — To measure heat 
means something more than simply to take the 
temperature. As heat is work, or energy, there 
must be a means whereby that energy can be ex- 
pressed. 

It has been said that the basis of all true science 
consists in correct definitions. The terms used, 
therefore, must be uniform, and should be used 
to express certain definite things. When those 
are understood then it is an easy matter for the 
student to grope his way along, as he meets the 
different obstacles, for he will know how to 
recognize them. 

Before specifically explaining the measurement 
it might be well to understand some of the terms 
used in connection with heat. The original theory 
of heat was, that it was composed of certain 
material, although that matter was supposed to 
be subtile, imponderable and pervading every- 
thing. 

This imponderable substance was called Caloric. 
It was supposed that these particles mutually 
attracted and repelled each other, and were also 
attracted and repelled by other bodies, so that 
they contracted and expanded. 

The phenomenon of heat was thus accounted 
for by the explanation that the expansion and 



THE ENERGY OF THE SUN 213 

contraction made the heat. This was known as 
the Material Theory of Heat, 

But that phase of the explanation has now been 
abandoned, in favor of what is known as the 
dynamical, or mechanical theory, which is re- 
garded merely as a mode of motion, or a sort 
of vibration, wherein the particles move among 
each other, with greater or less rapidity or in 
some particular manner. 

Thus, the movements of the atoms may be ac- 
celerated, or caused to act in a certain way, by 
friction, by percussion, by compression, or by 
combustion. Heat is the universal result of either 
of those physical movements. 

Notwithstanding that the material theory of 
heat is now abandoned, scientists have retained, 
as the basis of all heat measurements, the name 
which was given to the imponderable substance, 
namely, Caloric. 

It is generally written Calorie, in the text books. 
A calorie has reference to the quantity of heat 
which will raise the temperature of one kilogram 
of water, one degree Centigrade. 

As one kilogram is equal to about two pounds, 
three and a quarter ounces, and one degree Centi- 
grade is the same as one and two-thirds degrees 
Fahrenheit, it would be more clearly expressed by 
stating that a caloric is the quantity of heat re- 



214 MOTOES FOR BOYS 

quired to raise the temperature of one and one- 
fifth pound of water one degree Fahrenheit. 

This is known as the scientific unit of the 
thermal or heat value of a caloric. But the en- 
gineering unit is what is called the British Ther- 
mal Unit, and designated in all hooks as B. T. U. 

This is calculated by the amount of heat which 
is necessary to raise a kilogram of water one 
degree Fahrenheit. According to Berthelot, the 
relative value of calorics and B. T. U. are as 
follows : 

HEATS OF COMBUSTION 

Substance. Calories. B. T. U. 

Hydrogen 3'4,500 62,100 

Carbon to carbon dioxide 8,137 14,647 

Carbon to carbon monoxide 2,489 4,480 

Carbon monoxide 2,435 4,383 

Methane 13,343 24,017 

Ethylene 12,182 21,898 

Cellulose 4,200 7,560 

Acetylene • 12,142 21,856 

Peat 5,940 10,692 

Naphthalene 9,690 10,842 

Sulphur 2,500 4,500 

When it is understood that heat is transmitted 
in three different ways, the value of a measuring 
instrument, or a unit, will become apparent 

Thus, heat may be transmitted either by con- 
duction, convection, or radiation. 



THE ENERGY OF THE SUN 215 

Conduction is the method whereby heat is trans- 
mitted from one particle to another particle, or 
from one end of a rod, or other material to the 
other end. Some materials will conduct the heat 
much quicker than others, but if we have a stand- 
ard, such as the calorie, then the amount of heat 
transmitted and also the amount lost on the way 
may be measured. 

Convection applies to the transmission of heat 
through liquids and gases. If heat is applied 
to the top or surface of a liquid, the lower part 
will not be affected by it. If the heat is applied 
below, then a movement of the gas or liquid be- 
gins to take place, the heated part moving to the 
top, and the cooler portions going down and thus 
setting up what are called convection currents. 

Radiation has reference to the transference 
of heat from one body to another, either through 
a vacuum, the air, or even through a solid. 

By means of the foregoing table, which gives 
the heats developed by the principal fuels, it is 
a comparatively easy matter to determine the 
calorific value of fuels, which is ascertained by 
making an analysis of the fuel. 

The elements are then taken together, and the 
table used to calculate the value. Suppose, for 
instance, that the analysis shows that the fuel has 
seventy-five per cent, of carbon and twenty-five 



216 MOTOES FOR BOYS 

per cent, of hydrogen. It is obvious that if we 
take seventy-five per cent, of 8,137 (which is the 
index for carbon), and twenty-five per cent, of 
43,500 (the index of hydrogen), and adding the 
two together, the result, 14,727, would represent 
the calorific value of the fuel. 



GLOSSARY OF WORDS 

USED IN TEXT OF THIS VOLUME 



Absolute. 
Amplitude. 

Absorbent. 
Absorbing. 
Absorption. 
Abutment. 
Accuracy. 
Accession. 
Accelerate. 
Accessible. 
Accelerated. 
Actuating. 
Advance 
Spark. 



Aeration. 
Alkali. 



Allusion. 
Anomaly. 
Adhesion. 
Adjustment. 



Independent; free from all limitations. 

Greatness of extent; the state or quality of being 
sufficient. 

A material which will take up a liquid. 

Taking up, or taking in. 

The act or process of taking up or fully occupying. 

A wall; a stop. 

Correctness ; positiveness. 

Added to; addition, or increase. 

Quickened; hurried. 

Available; capable of being reached. 

A quickening, as of process or action. 

Moved or incited by some motive. 

The term applied to the movement of the mechanism 
in an internal combustion engine, which will 
cause the electric spark to act before the crank has 
passed the dead center. 

To add air; to impregnate with oxygen. 

In chemistry it is known as a compound of hydro- 
gen and oxygen, with certain chemicals. Anything 
which will neutralize an acid. 

Referring to; noticed. 

A deviation from an ordinary rule; irregular. 

To cling to; to stick together. 

To arrange in proper order; to set into working con- 
dition. 

217 



218 



GLOSSARY 



Alternating 
current. 

Ampere. 



Amplitude. 
Analysis. 
Annular. 
Armature. 

Assuming. 
Asphaltum. 



Atmospheric. 
Available. 



A current which goes back and forth in opposite di- 
rections; unlike a direct current which flows con- 
tinuously in one direction. 

The unit of current; the term in which strength of cur- 
rent is measured. An ampere is an electro-motive 
force of one volt through a resistance of one ohm. 

The state or quality of being broad, or full. 

The separation into its primitive or original parts. 

Pertaining to or formed like a ring. 

The part of a dynamo or motor which revolves, and 
on which the wire coils are wound. 

Taking on ; considered to be correct or otherwise. 

A bituminous composition used for pavements, prop- 
erly made from natural bitumen, or from asphalt 
rock. 

Referring to; noticed. 

Capable of being employed or used. 



Bearings. 

Bifurcated. 
Blow-off 
valve. 

Bombard. 
Bonnet. 



Butterfly- 
valve. 
Caloric. 
Cam. 



The part in mechanism in which journals or spindles 

rest and turn. 
In two parts; branching, like a fork. 
A valve so arranged that at certain pressures the 

valve will automatically open and allow the steam 

to escape from the boiler. 
An assault; an attack by shot or shell. 
The cap of a valve, which is so arranged that while 

it permits the valve stem to turn, will also prevent 

leakage. 
A form of valve which is usually flat, and adapted 

to open out, or turn within the throat or pipe. 
Pertaining to heat. 

A rotating wheel, or piece, either regular or irregu- 
lar, non-circular, or eccentric. 



GLOSSAKY 



219 



Carbon. 

Carbureter. 
Carbonized. 
Carbureted. 
Centripetal. 
Centrifugal. 
Check valve. 

Chemical. 

Chambered. 
Circumfer- 
ence. 
Circularly. 
Circulation. 
Clearance. 

Classification. 

Coincide. 

Cohesion. 

Cooperate. 
Compounding-. 



A material like coke, ground or crushed. It re- 
quired high heat to burn it, and it is used for the 
burning material in electric arc lamps. 

The device used to mix air and gaseous fuel in an 
internal combustion engine. 

Put into a charred form; coke is carbonized coal; 
charcoal is carbonized wood. 

Air or gas to which has been added the gaseous 
product of petroleumi, or 'some distillate. 

That which draws inwardly, or to the center, like the 
gravitational action of the earth. 

That which throws outwardly; the opposite of cen- 
tripetal. 

A form of valve which will permit liquids to freely 
flow in one direction, but which will open automat- 
ically, so as to allow the liquid to flow in the op- 
posite direction. 

Pertaining to the composition of matter; or relat- 
ing to chemistry. 

Having compartments, or divided up into recesses. 

Around the outside. 

Around; about the circumference. 

The movement of water to and fro through conduits. 

The space at the head of a cylinder within which the 
steam or gases are compressed by the piston. 

To put in order in a systematic way. 

To correspond with identity of parts. 

To stick together. The attraction of material sub- 
stances of the same kind for each other. 

To work together harmoniously. 

Composed of or produced by the union of two or more 
parts, or elements. 



220 



GLOSSARY 



Complicated. 
Commutator. 



Combustion. 



Concaved. 
Condensation. 
Condenser. 
Concentric. 

Conductor. 

Conically. 
Conduit. 

Conduction. 

Constant. 

Conserve. 

Commodity. 

Connecting 

Rod. 
Contrivance. 

Contradis- 
tinction. 
Cornish. 

Contact 
Breaker. 



Very much involved; not simple. 

The revolving part on the armature of a dynamo or 
motor, which is divided up into a multiplicity of 
insulated plates, which are connected with the coils 
of the wire around the armature. 

Burning; the action of the unity of oxygen with any 
substance, which causes it to be destroyed or 
changed. 

Hollowed. 

The change from a gaseous to a liquid or solid state. 

An apparatus which converts a gas into a liquid. 

A line which at any point is at the same distance 
from a common center. 

A substance which will convey either heat or electric- 
ity from one end to the other. 

In the form of a cone. 

A trough, tube, or other contrivance, which will con- 
vey liquids or gases from place to place. 

The capacity to transmit from one point to another. 

Being the same thing at all times ; not varying. 

To take care of; to use judiciously. 

Any product, or kind of goods. 

That part of mechanism which connects the piston 
rod with the crank. 

Any mechanism, or device which will serve a certain 
purpose. 

That which is opposite to, comparatively; taken in 
conjunction with for the purpose of comparison. 

A form of boiler which has the fire tubes within the 
water space. 

A device which has the current normally in circuit, 
and is so arranged that the circuit is broken at 



GLOSSARY 



221 



certain intervals, and again immediately reestab- 
lished. 

Co-relate. Belonging to; having reference to the same order. 

Conventional. The regular manner or method. 

Contact A device for making contacts in an electric circuit 

Maker. at regular intervals. 

Convolution. The turns or twists taken. The changes or move- 
ment or the peculiar flow of a liquid. 

Control. Handling with regularity; The act of guiding. 

Contracted. Made smaller. 

Contingency. An event; under certain conditions. 

Counteract. To antagonize; to so act as to go against. 

Converting 1 . Changing; to put in an opposite condition. 

Conical. In the form of a cone. 

Cylindrical. In the form of a cylinder; barrel-shaped. 

Cyclopedia. A work which gives, in alphabetical order, the ex- 
planations of terms and subjects. 

Cycle. A period extending over a certain time; a certain 

order of events. 

Dead Center. That point in the turn of a crank where the piston 
has no effective pull in either direction. 

Deenergize. To take power away from. 

Deflecting. To glance off; to change the regular or orderly 

course. 

Demagne- To take magnetism away from. 

tized. 

Deteriora- To take away from; to grow smaller; to lessen; to 

tion. depreciate in quality. 

Deviate. To avoid; to get around; not going or doing in the 

regular way. 

Diagram. A mechanical plan or outline, as distinguished from 

a perspective drawing. 

Diametric- Across or through the object; through the center, 

ally. 



222 



GLOSSARY 



Dioxide. An oxide containing two atoms of oxygen to the 

molecule. 

Direct ctir- An electric current which flows continuously in one 
rent. direction. 

Dissipated. Changed, or entirely dispensed with; usually ap- 
plied to a condition where materials or substances 
are scattered. 

Distributer. A piece of mechanism in an electric circuit, which 
switches the current from one part to the other. 

Dissect. To take apart. 

Dominating. Overpowering; having greatest power. 

Diverse. Different; unlike. 

Dry Cell. A battery in which the electrolyte is not in a fluid 

state. 

Duct. Either an open trough or conduit, or a closed path 

for the movement of gases or liquids. 

Dynamo. A mechanical device for the purpose of generating 

electricity. 

Eccentric. A wheel having its perimeter so formed that the cen- 

ter is not in the exact middle portion. 

Economy. Prudence; carefulness; not disposed to be excessive. 

Efficiency. Well adapted for the situation ; mechanism which will 

do the work perfectly, or cheaply. 

Effectiveness. Well done; to the best advantage. 

Ejecting. Throwing out; sending forth. 

Elastic. That quality of material which tends to cause it to 

return to its original shape when distorted. 

Elementary. Primitive; the first; in the simplest state. 

Electric arc. A term applied to the current which leaps across the 
slightly separated ends of an electric conductor. 

Electricity. An agent, incapable of being seen, but which pro- 
duces great energy. 

Electrolyte. The agent, or material in a battery, usually a liquid, 



GLOSSARY 



223 



which the current passes through in going from one 
electrode to the other. 

Elliptical. A form which might be expressed by the outline 

shape of an egg, measured from end to end. 

Emolument. Pay; remuneration; the amount received for employ- 
ment of any kind. 

Emission. To send out from; a sending or puttting out. 

Energy. Force; power. 

Essential. The main thing; the important element. 

Evaporate. To convert into vapor, usually by heat. 

Exhaust. The discharge part of an engine, or other apparatus. 

Excessive. Too much; more than is required. 

Expansion. Enlarged; the occupying of a greater space. 

Explicit. Particularly definite; carefully explained and under- 

stood. 

External. Outside; the outer surface. 

Facilitating". Helping; aiding in anything. 

Factor. An element in a problem. 

Fahrenheit. One of the standards of heat measurement. A ther- 
mometer scale, in which the freezing point of water 
is 32, and the boiling temperature is 212. 

Fascinating. Attractiveness; capacity to allure. 

Feathered. Applied to the shape of an article, or to a rib on the 

side of a shaft, which is designed to engage with a 
groove. 

Fertilizer. Material for enriching soil and facilitating the 

growth of vegetables. 

Field. A term applied to the windings and the pole pieces 

of a dynamo or motor, which magnetically influ- 
ence the armature. 

Focal. The point; the place to which all the elements or 

forces tend. 

Foot pounds. The unit of mechanical work, being the work done 



224 



GLOSSARY 



in moving one pound through a distance of one 
foot. 

Four-cycle. A gasoline engine, in which the ignition of the com- 

pressed hydro-carbon gases takes place every other 
revolution. 

Formation. The arrangement of any mechanism, or a series of 

elements. 

Formula. The recipe for the doing of a certain thing; a direc- 

tion. 

Friction. A retarding motion; the prevention of a free move- 

ment. 

Function. The qualities belonging to an article, machine or 

thing; that which a person is capable of perform- 
ing. 

Fundamental. The basis; the groundwork of a thing. 

Gaseous. Of the nature of a gas. 

Gearing 1 . Usually applied to two or more sets of toothed wheels 

which cooperate with each other. 

Generating 1 . Producing; manufacturing; bringing out of. 

Globules. The small particles of liquids; or the molecules com- 

prising fluids. 

Gravitation. The force of the earth which causes all things to 
move toward it; the attraction of mass for mass. 

Heart Wheel. A wheel having the outline of a heart. 

Helical. A spirally-wound form. 

High Ten- A term applied t6 a current of electricity, which has 

sion. a very high voltage, but low amperage. 

Horizontal. Level, like the surface of water; at right angles to 
a line which points to the center of the earth. 

Horse Power. The unit of the rate of work, equal to 33,000 pounds 
lifted one foot in one minute. 

Hydro-car- A gas made from the vaporization of crude petro- 
bon. leum or of its distillates. 



GLOSSARY 



225 



Hydrogen. One of the original elements. The lightest of all 

gases. 

Ignite. To set on fire. 

Ignition. The term applied to the firing of a charge of gas in 

a gas or gasoline engine. 

Impact. A blow; a striking force. 

Impregnated. To instill; to add to. 

Impulse. A natural tendency to do a certain thing; determina- 

tion to act in a certain way through some influence. 

Impinge. To strike against; usually to contact with, at an 

angle. 

Incompar- Too good or great to measure, 

able. 

Inclined. Not level; leaning; not horizontal. 

Induction. The peculiar capacity of an electric current to pass 

from one conductor to another through the air. 

Indication. That which shows; to point out. 

Injector. A device whereby the pressure of the steam in a boiler 

will force water into the boiler. 

Initially. At first; the original act. 

Injection. To put into; to eject from an apparatus, into some 

other element. 

Insulated. So covered as to prevent loss of current by contact 

with outside substances or materials. 

Intimate. Close to; on good terms with. 

Integral. A complete whole; containing all the parts. 

Instinct. Knowledge within; something which influences con- 

duct or action. 

Interstellar. The space beyond the earth; that portion of the 
heavens occupied by the stars. 

Internal. Within; that portion of mechanism' which is inside. 

Interposing. To step into; to place between, or in the midst of. 

Intensity. Fierce; strong; above the ordinary. 



226 



GLOSSAEY 



Interrupted. 
Interstices. 
Instantane- 
ous. 
Intricate. 
Inquisitive. 
Jacketing. 
Jump Spark. 



Kinetic. 

Latent. 

Lateral. 



Lines of 
force. 

Low Tension. 

Lubrication. 

Mangle. 

Magneto. 

Magnetism. 

Manifesta- 
tion. 

Make and 
Break. 

Manifold. 



To stop; to take advantage of. 

The spaces in between. 

Immediately; at once; without waiting. 

Difficult; not easy. 

The desire to inquire into. 

To coat or cover on the outside. 

One of the methods of igniting hydro-carbon gases. A 
current of sufficiently high voltage is used to cause 
the current to jump across the space between the 
separated ends of a conductor. 

Consisting in or depending on motion. 

That which is within itself. 

Branching out from the sides; usually applied as the 
meaning for the direction which is at right angles 
to a fore and aft direction. 

Applied to electricity, air, water, or any moving ele- 
ment, which has a well directed movement in a 
definite direction. 

In methods for igniting hydro-carbon charges, any 
circuiting which has a low voltage. 

The oiling of mechanical parts to reduce friction. 

A machine for smoothing out clothing, goods, etc. 

A dynamo which has the field pieces, or poles made 
of permanent magnets. 

That quality, or agency by virtue of which certain 
bodies are productive of magnetic force. 

Showing or explaining a state of things; an out- 
ward show. 

An ignition system, which provides for throwing in 
and cutting out an electric circuit. 

A system of piping whereby the exhausts of a gaso- 



GLOSSARY 



227 



Manganese. 



Manually. 

Material. 

Mechanically, 

Mobility. 
Multiple. 



Neutral. 
Normal. 

Ohm's law. 



Oscillating:. 

Orifice. 

Organism. 

Oxidation. 



Oxygen. 



line engine are brought together into one common 
discharge. 
A hard, brittle, grayish white metallic element, used 
in the manufacture of paints and of glass, and also 
for alloying metals. 
Doing things by hand; muscular activity. 
Substances and parts from which articles are made. 
Doing things by means of machinery, or in some 

regular order. 
The capacity to move about. 

A figure used a certain number of times, is said to 

be a multiple of a number, if it will divide the 

number equally. Thus 4 is a multiple of 16; 3 is 

a multiple of 9, and so on. 

Neither; not in favor of any party or thing. 

As usual; in the regular way; without varying from 

the ordinary manner. 
In electricity, it is expressed as follows: 1. The 
current strength is equal to the electromotive force 
divided by its resistance. 2. The electromotive 
force is equal to the current strength multiplied 
by the resistance. 3. The resistance is equal to 
the electromotive force divided by the current 
strength. 
Moving to and fro, like a pendulum. 
An opening; a hole. 

Any part of the body, or any small germ or animal- 
cule. 
The action of air or oxygen on any material, is 
called oxidation. Thus rust on iron is called oxi- 
dation. 
A colorless, tasteless gas, the most important in na- 
ture, called the acid-maker of the universe, as it 



228 



GLOSSARY 



unites with all substances, and produces either an 
acid, an alkali, or a neutral compound. 

Parallel. Two lines are said to be parallel, when they are ly- 

ing side by side and are equally distant from each 
other from end to end. 

Pendulum. A bar suspended at one end to a pivot pin, and hav- 

ing its lower end free to swing to and fro. 

Penstock. A reservoir designed to receive and discharge water 

into a turbine or other form of water wheel. 

Permanent. That which will last; not easily stopped. 

Pestle. An implement of stone or metal used for breaking 

and grinding up chemicals, and other material in 
a mortar. 

Petroleum. A liquid fuel product, found in many places, its 

component parts being about 15 per cent, hydro- 
gen and 85 per cent, carbon. 

Perimeter. The outer rim, or circle. 

Piston. That part of an engine which is attached to the 

piston rod. 

Pinion. A small gear wheel driven by a larger gear wheel. 

Platinum. An exceedingly hard metal, used in places for elec- 

trical work where the current is liable to burn out 
ordinary conductors. 

Polarity. The quality of having opposite poles. 

Pre-heating. To heat before the ordinary process of heating com- 
mences. 

Ponderous. Large; heavy; difficult to handle. 

Port. In nautical parlance the left side of a vessel; the 

larboard side; also an opening, or a conduit for 
the transmission of gas or liquid. 

Pop valve. A valve designed to open and allow escape of the 

imprisoned gases when the latter reach a certain 
pressure. 



GLOSSARY 



229 



Potential. The power; the term used in electricity to denote the 

energy in a motor. 

Plurality. More than one; many. 

Precipice. A high and very steep cliff. 

Pressure. The act of one body placed in contact with another 

and acting against it or against each other. 

Precaution. Taking great care; being assured of safety. 

Primary bat- A cell, or a number of cells, made of pairs of me- 
tery. tallic couples, immersed in an electroly.te of either 

an acid or an alkali. 

Proney A device for testing machinery and determining 

Brake. power, by means of friction. 

Primeval. The earliest; the first; of a low order. 

Proportion. The relation of one thing or number, to another ; com- 
parative merit. 

Proximity. Close to; near at hand. 

Quadruple. Four times. 

Rack. A bar having a number of teeth, to serve as a step 

or measure for a pawl, or a toothed wheel. 

Radial. Extending out from the center. 

Radiation. The property of many substances to give forth heat 

or cold, or to disperse it. 

Rarified. Made less than the normal pressure, as air, which is 

not as dense at a high as at a low altitude. 

Receiver. In telephone apparatus, that part of the mechanism 

which transmits the message to the ear. 

Rectilinear. A right line; a straight direction forwardly. 

Reaction. A force which is counter to a movement in another 

direction. 

Refrigeration. Cooling process; the art of freezing. 

Refined. Purifying; improved. 

Re-heating. The process of further heating or increasing the tem- 
perature during the progress of the work. 



230 



GLOSSARY 



Requisite. 
Residue. 
Resistance. 
Reciprocat- 
ing. 
Refinement. 
Retort. 

Revolution. 
Rock Shaft. 

Rotation. 



Sal-Ammon- 

iac. 
Secondary 

Battery. 



Secondary 
coil. 



Scavenging. 
Sector. 



Secondary. 
Segment. 



The necessary part; the requirement. 

The balance; what is left over. 

Opposition; against. 

One for the other; moving from one side to the 
other. 

Chastity of thought, taste, manner, or actions. 

A vigorous answer. A receptacle adapted to stand a 
high heat. 

Turning, like the earth in its orbit. 

A shaft which turns part of its rotation in one di- 
rection, and then turns in the other direction. 

The turning of a wheel on its axle; the rotation of 
the earth on its axis each day. Distinguishing 
from revolution which is a swinging of the entire 
body of the earth around the sun in its orbit. 

A white metallic element. 

A battery which is charged with a current, and then 
gives forth an electric current of a definite amount. 
It is also known as an accumulator, since its ele- 
ments continue to accumulate electric energy. 

In induction coils two wire wrappings are necessary, 
the first winding being, usually, of heavy wire, and 
called the primary; the second winding is of finer 
wire, and is called the secondary coil. 

To clean out; to scour. 

An A-shaped piece cut from a disk; distinguish this 
from a segment, which is a part cut off from a disk 
by a single straight line. 

Occupying a second place; not of the first kind, or 
place. 

A part cut off from a disk, by a single line; the 
part of a circle included within a chord and its arc. 



GLOSSAEY 



231 



Sewerage. The conveyance of waste matter from a building. 

Sinuous. Systematic draining by means of pipes or conduits. 

Characterized by bends, or curves, or a serpentine 
curving, or wave-like outline. 

Slide Valve. A form, which moves along a flat surface through 
which the duct is formed. 

Solution. A liquid having therein different substances mixed 

together. 

Sprayer. To eject; to send forth in small particles. 

Stability. Fixed; strength to stand without support. 

Stupendous. Immense; large; much beyond the largest of the 
kind. 

Standard. A sample of the measure or extent; a type or a 

model. 

Stratify. To deposit, form, or range in strata. 

Super Heat- To heat up beyond the ordinary or normal point, 
ing. 

Subtle. Crafty; made of light material; daintily con- 

structed. 

Supersede. In place of; to take the place of. 

Susceptible. Capable of being changed or influenced. 

Suspension. Hanging; floating of a body in fluid. 

Suction. The production of a partial vacuum in a space con- 

nected with a fluid under pressure. 

Terminal. The end ; the last part. 

Technical. Specially or exclusively pertaining to some art or 

subject. 

Throttling. The closing of a port; the cutting down of a sup- 
ply- 

Throttle A device which is designed to cut off the flow of a 

fluid. 
Valve. That which is speculative, as distinguished from prac- 

Theoretical. tical. 



232 



GLOSSAKY 



Transforma- 
tion. 
Transmit. 
Transference. 

Transferred. 

Triple. 

Turbine. 



Tubular. 
Two-Cycle. 



Typical. 
"Undershot. 

Unison. 
Universally. 
Utility. 
Vacuum. 



Vaporizing. 
Variable. 
Venturi Tube. 

Vertical. 
Vibrator Coil. 



A complete change; made over into something 
else. 

To convey; to send to another part. 

To convey to another part; the change from one 
thing to another. 

Put over. 

Three; thrice. 

To turn; a form of water wheel and steam engine, 
where the fluid impinges against the blades ar- 
ranged around the perimeter of the wheel. 

Hollowed; like a pipe. 

A gasoline engine, in which the compressed hydro- 
carbon gases are fired every turn of the crank 
shaft. 

The nature or characteristics of a type. 

A type of wheel in which the water shoots past and 
against the blades on the lower side. 

Together; conjointly; acting with each other. 

All over the world; throughout all space. 

Use; that which is valuable or of service. 

That part from which all material is taken; in a 
limited sense, air, which has less density than the 
normal. 

To convert into gas, usually by heat. 

With differing characteristics; changeable. 

A form of tube which has a contracted part between 
its ends. 

In the direction of a line which points to the center 
of the earth. 

In electrical devices used in the ignition systems of 
certain types of gasoline engines, a winding is 
provided on a metallic core, which has an armature 
that is made so it will vibrate. 



GLOSSARY 



233 



Volt. 

Voltage. 
Volt Meter. 

Watt. 



Weight. 

Winnowed. 
Wiping Bar. 



The pressure of an electric current ; the unit of elec- 
tromotive force. 

Electromotive force as expressed in volts. 

An instrument for indicating the voltage of an elec- 
tric circuit. 

The electrical unit of the rate of working in an elec- 
tric circuit, the rate being the electromotive force 
of one volt, and the intensity of one ampere. 

The measure of the force toward the center of the 
earth, due to gravity. 

Taken out; sifted from. 

A metallic piece which rests against a moving wheel 
and designed to take a current from or to transmit 
it to the wheel. 



The Motor Boys Series 

(Trade Mark, Reg. U. S. Pat. Of.) 

By CLARENCE YOUNG 

12mo. Illustrated. Price per volume, 60 cents, postpaid. 



§? 



The Motor Boys 

or Chums Through Thick and Thin 

The Motor Boys Overland 

or A Lone Trip for Fun and Fortune 

The Motor Boys in Mexico. 

or The Secret of The Buried City 

The Motor Boys Across the Plains 

or The Hermit of Lost Lake 



The Motor Boys Afloat 

or The Stirring Cruise of the 

Dartaway 

The Motor Boys on the Atlantic 

or The Mystery of the Lighthouse 

The Motor Boys in Strange Waters 

or Lost in a Floating Forest 

The Motor Boys on the Pacific 

or The Young Derelict Hunters 




THE „ 

MOTOR BOVS 
O0UDS 



The Motor Boys in the Clouds 

or A Trip for Fame and Fortune 

The Motor Boys Over the Rockies 

or A Mystery of the Air 

The Motor Boys Over the Ocean 

or A Marvellous Rescue in Mid-Air 

The Motor Boys on the Wing 

or Seeking the Airship Treasure 



The Motor Boys After a Fortune 

or The Hut on Snake Island 

The Motor Boys on the Border 

or Sixty Nuggets of Gold 

The Motor Boys Under the Sea 

or From Airship to Submarine 

The Motor Boys on Road and River 

(new) or Racing to Save a Life 




CUPPLES & LEON CO., Publishers, 



NEW YORK 



Up-to-date Baseball Stories 

Baseball Joe Series 



12mo. 



By LESTER CHADWICK 

Author of "The College Sports Series" 

Illustrated. Price per volume, 60 cents, 



postpaid. 




Ever since the success of Mr. Chadwick's 
"College Sports Series" we have been urged 
to get him to write a series dealing exclu- 
sively with baseball, a subject in which he is 
unexcelled by any living American author 
or coach. 

BASEBALL JOE OF THE SILVER STARS 

or The Rivals of Riverside 
In this volume, the first of the series, Joe 
is introduced as an everyday country boy 
who loves to play baseball and is particularly 
anxious to make his mark as a pitcher. He finds it almost 
impossible to get on the local nine, but, after a struggle, he 
succeeds. A splendid picture of the great national game in 
the smaller towns of our country. 

Baseball Joe on the School Nine 

or Pitching for the Blue Banner 
Joe's great ambition was to go to boarding school and play 
on the school team. He got to boarding school but found it 
harder making the team there than it was getting on the nine 
at home. He fought hi6 way along, and at last saw his chance 
and took it, and made good. 

Baseball Joe at Yale 

or Pitching for the College Championship 
From a preparatory school Baseball Joe goes to Yale Uni- 
versity. He makes the freshman nine and in his second year 
becomes a varsity pitcher and pitches in several big games. 

Baseball Joe in the Central League 

or Making Good ms a Professional Pitcher 
In this volume the scene of action is shifted from Yale Col- 
lege to a baseball league of our central states. Baseball Joe's 
work in the box for Old Eli had been noted by one of the 
managers and Joe gets an offer he cannot resist. Joe accepts 
the offer and makes good. 

Baseball Joe in the Big League 

or A Young Pitcher's Hardest Struggle 
From the Central League Joe is drafted into the St. Louis 
Nationals. At first he has little to do in the pitcher's box, but 
gradually he wins favor. A corking baseball story that fans, 
both young and old, will enjoy. 



CUPPLES & LEON CO., Publishers, 



NEW YORK 



The Racer Boys Series 

by CLARENCE YOUNG 

Author of "The Motor Boys Series", "Jack Ranger Series", etc. etc. 
Fine cloth binding. Illustrated. Price per volume, 60c postpaid. 




The announcement of a new series of stories by 
Mr. Clarence Young is always hailed with delight 
by boys and girls throughout the country, and we 
predict an even greater success for these new books, 
than that now enjoyed by the "Motor Boys Series." 

The Racer Boys 

or The Mystery of the Wreck 
This, the first volume of the series, tells who 
the Racer Boys were and how they chanced to be 
out on the ocean in a great storm. Adventures 
follow in rapid succession in a manner that only Mr. Young can describe. 

The Racer Boys At Boarding School 

or Striving for the Championship 
When the Racer Boys arrived at the school everything was at a stand- 
still, and the students lacked ambition and leadership. The Racers 
took hold with a will, got their father to aid the head of the school 
financially, and then reorganized the football team. 

The Racer Boys To The Rescue 

or Stirring Days in a Winter Camp 
Here is a story filled with the spirit of good times in winter — skating, 
ice-boating and hunting. 

The Racer Boys on The Prairies 

or The Treasure of Golden Peak 
From their boarding school the Racer Boys accept an invitation to 
risk a ranch in the West. 

The Racer Boys on Guard 

or The Rebellion of Riverview Hall 
Once more the boys are back at boarding school, where they have 
many frolics, and enter more than one athletic contest. 

The Racer Boys Forging Ahead 

or The Rivals of the School League 

Once more the Racer Boys go back to Riverview Hall, to meet their 

many chums as well as several enemies. Athletics play an important 

part in this volume, and the rivalry is keen from start to finish. The 

Racer Boys show what they can do under the most trying circumstances. 



CUPPLES & LEON CO., Publishers 



NEW YORK 



The Dorothy Dale Series 



12mo. 



By MARGARET PENROSE 

Author of "The Motor Girls Series" 

Illustrated. Price per volume, 60 cents, postpaid. 




Dorothy Dale: A Girl of To-Day 

Dorothy is the daughter of an old Civil 
War veteran who is running a weekly news- 
paper in a small Eastern town. When her 
^l EfflM*. ^a f atner falls sick, the girl shows what she 
can do to support the family. 

Dorothy Dale at Glenwood 
School 

More prosperous times have come to the 
Dale family, and Major Dale resolves to send 
Dorothy to a boarding school. 

Dorothy Dale's Great Secret 

A splendid story of one girl's devotion to another. How 
Dorothy kept the secret makes an absorbing story. 

Dorothy Dale and Her Chums 

A story of school life, and of strange adventures among the 
gypsies. 

Dorothy Dale's Queer Holidays 

Relates the details of a mystery that surrounded Tangle- 
wood Park. 

Dorothy Dale's Camping Days 

Many things happen, from the time Dorothy and her chums 
are met coming down the hillside on a treacherous load of hay. 

Dorothy Dale's School Rivals 

Dorothy and her chum, Tavia, return to Glenwood School. 
A new student becomes Dorothy's rival and troubles at home 
add to her difficulties. 

Dorothy Dale in the City 

Dorothy is invited to New York City by her aunt. This 
tale presents a clever picture of life in New York as it appears 
to one who has never before visited the Metropolis. 

DOROTHY DALE'S PROMISE 
Strange indeed was the promise and given under strange 
circumstances. Only a girl as strong of purpose as was Dorothy 
Dale would have undertaken the task she set for herself. 

Dorothy Dale in the West 

Dorothy's father and her aunt inherited a valuable tract 
of land in the West. The aunt, Dorothy and Tavia, made a 
long journey to visit the place, where they had many adventures. 



CUPPLES & LEON CO., Publishers, 



NEW YORK 



The Motor Girls Series 



12mo. 



By MARGARET PENROSE 

Author of the highly successful "Dorothy Dale Series" 

Illustrated. Price per volume, 60 cents, postpaid. 




The Motor Girls 

or A Mystery of the Rood 
When Cora Kimball got her touring ear she 
did not imagine so many adventures were in 
store for her. A tale all wide awake girls 
will appreciate. 

The Motor Girls on a Tour 

or Keeping a Strange Promise 
A great many things happen in this vol- 
ume. A precious heirloom is missing, and how it was traced 
up is told with absorbing interest. 

The motor Girls at Lookout Beach 

or In Quest of the Runaways 
There was a great excitement when the Motor Girls decided 
to go to Lookout Beach for the summer. 

The Motor Girls Through New England 

or Held by the Gypsies 
A strong story and one which will make this series more 
popular than ever. The girls go on a motoring trip through 
New England. 

The Motor Girl9 on cedar Lake 

or The Hermit of Fern Island 
How Cora and her chums went camping on the lake shore 
and how they took trips in their motor boat, are told in a way 
all girls will enjoy. 

The Motor Girls on the Coast 

or The Waif from the Sea 
The scene is shifted to the sea coast where the girls pay 
a visit. They have their motor boat with them and go out 
for many good times. 

The Motor Girls on Crystal Bay 

or The Secret of the Red Oar 
More jolly times, on the water and at a cute little bungalow 
on the shore of the bay. A tale that will interest all girls. 

The Motor Girls on Waters Blue 

or The Strange Cruise of the Tartar 

Before the girls started on a long cruise down to the 

West Indies, they fell in with a foreign girl and she informed 

them that her father was being held a political prisoner on 

one of the islands. A story that is full of fun as well as mystery. 



CUPPLES & LEON CO., Publishers, 



NEW YORK 



Ruth Fielding Series 

By ALICE B. EMERSON 
12mo. Illustrated. Price per volume, 40 cents, postpaid. 




a Ruth Fielding of The Red Mill 



or Jaspar Parloe's Secret 

Telling how Ruth, an orphan girl, came 
to live with her miserly uncle, and how 
the girl's sunny disposition melted the old 
miller's heart. 

Ruth Fielding at Briarwood Hall 

or Solving the Campus Mystery 

Ruth was sent by her uncle to boarding 
school. She made many friends, also one 
enemy, who made much trouble for her. 



Ruth Fielding at Snow Camp 

or Lost in the Backwoods 
A thrilling tale of adventures in the backwoods in winter, 
is told in a manner to interest every girl. 

Ruth Fielding at Lighthouse Point 

or Nita, the Girl Castaway 
From boarding school the scene is shifted to the Atlantic 
Coast, where Ruth goes for a summer vacation with some chums. 

Ruth Fielding at Silver Ranch 

or Schoolgirls Among the Cowboys 
A story with a western flavor. How the girls came to the 
rescue of Bashful Ike, the cowboy, is told in a way that is most 
absorbing. 

Ruth Fielding on Cliff island 

or The Old Hunter's Treasure Box 
Ruth and her friends go to Cliff Island, and there have 
many good times during the winter season. 

Ruth Fielding at Sunrise Farm 

or What Became of the Raby Orphans 
Jolly good times at a farmhouse in the country, where Ruth 
rescues two orphan children who ran away. 

Ruth Fielding and the Gypsies 

or The Missing Pearl Necklace 
This volume tells of stirring adventures at a Gypsy encamp- 
ment, of a missing heirloom, and how Ruth has it restored to 
its owner. 



CUPPLES & LEON CO., Publishers, 



NEW YORK 



The Dave Dashaway 
Series 

By ROY ROCKWOOD 

Author of the "Speedwell Boys Series" and the "Great Marvel Series." 
12mo. Illustrated. Price per volume, 40 cents, postpaid. 



Never was there a more clever young aviator than Dave 
Dashaway. All up-to-date lads will surely wish to read 
about him. 




Dave Dashaway the Young Aviator 

or In the Clouds for Fame and Fortune 

This initial volume tells how the hero ran 
away from his miserly guardian, fell in with 
a successful airman, and became a young 
aviator of note. 



Dave Dashaway and 
Hydroplane 



His 



or Daring Adventures Over the Great Lakes 

Showing how Dave continued his career as a birdman and 
had many adventures over the Great Lakes, and how he 
foiled the plans of some Canadian smugglers. 

Dave Dashaway and His Giant Airship 

or A Marvellous Trip Across the Atlantic 

How the giant airship was constructed and how the daring 
young aviator and his friends made the hazardous journey 
through the clouds from the new world to the old, is told in a 
way to hold the reader spellbound. 

Dave Dashaway Around the World 

or A Young Yankee Aviator Among Many Nations 

An absorbing tale of a great air flight around the world, 
of adventures in Alaska, Siberia and elsewhere. A true to 
life picture of what may be accomplished in the near future. 

DAVE DASHAWAY: AIR CHAMPION 

or Wizard Work in the Clouds 

Dave makes several daring trips, and then enters a contest 
for a big prize. An aviation tale thrilling in the extreme. 



CUPPLES & LEON CO., Publishers, 



NEW YORK 



The Speedwell Boys 
Series 

By ROY ROCKWOOD 

Author of "The Dave Dashaway Series," "Great Marvel Series," etc. 
12mo. Illustrated. Price per volume, 40 cents, postpaid. 




All boys who love to be on the go will welcome the Speed- 
well boys. They are clean cut and loyal lads. 

The Speedwell Boys on Motor 
Cycles 

or The Mystery of a Great Conflagration 

The lads were poor, but they did a rich 
man a great service and he presented them 
with their motor cycles. What a great fire 
led to is exceedingly well told. 

The Speedwell Boys and Their 
Racing Auto 

or A Run for the Golden Cup 

A tale of automobiling and of intense rivalry on the road. 
There was an endurance run and the boys entered the contest. 
On the run they rounded up some men who were wanted by 
the law. 

The Speedwell Boys and Their Power Launch 

or To the Rescue of the Castaways 

Here is an unusual story. There was a wreck, and the lads, 
in their power launch, set out to the rescue. A vivid picture 
of a great storm adds to the interest of the tale. 

The Speedwell Boys in a Submarine 

or The Lost Treasure of Rocky Cove 

An old sailor knows of a treasure lost under water because 
of a cliff falling into the sea. The boys get a chance to go 
out in a submarine and they make a hunt for the treasure. 

The Speedwell Boys and Their Ice Racer 

or The Perils of a Great Blizzard 

The boys had an idea for a new sort of iceboat, to be run 
by combined wind and motor power. How they built the craft, 
and what fine times they had on board of it, is well related. 



CUPPLES & LEON CO., Publishers, 



NEW YORK 



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